Temporary relief of pain associated with sore and aching muscles due to strain from exercise or normal household and work activities.
Symptomatic relief and management of chronic, intractable pain and relief of pain associated with arthritis.

Device Description

The Portable Electro-Stimulation Therapy Device, model LGT-231 is a dual channel stimulator which sends gentle electrical current to underlying nerves and muscle group via electrodes applied on the skin with two operational modes and powered by rechargeable lithium battery; the device system is made up of mobile app MStim Reha, main unit and electrodes.

The Mobile App MStim Reha provides access to treatment controls for Portable Electro-Stimulation Therapy Device from a compatible device for selecting a pre-programmed output mode, adjusting frequency, pulse width and treatment time. Software operating environment of Mobile App MStim Reha are Android 4.3 or later mobile phone, with 4.0 Bluetooth and iOS 8.0 or later iPhone mobile phone, with 4.0 Bluetooth. Click the MStim Reha Application installation package on the phone to install the application. MStim Reha Application and the device can be connected via Bluetooth.

The main unit provides access to adjust the intensity up or down, put ON/OFF the main unit.

The two modes that Portable Electro-Stimulation Therapy Device, model LGT-231 employs are neuromuscular electrical stimulation (NMES) and transcutaneous electrical stimulation (TENS). Neuromuscular electrical stimulation (NMES) and transcutaneous electrical stimulation (TENS) target different nerve groups of the body.

TENS is specifically targets the sensory nerves, which are responsible for sending pain signals to the brain. TENS use tiny electrical impulses sent through the skin to nerves to modify the pain perception. TENS does not cure any physiological problem; it only helps control the pain, this activates the underlying sensory nerves. Self-adhesive electrodes are placed on the skin close to the area of pain.

NMES targets the muscle itself, specifically through the motor nerves. This allows the NMES machine to create a muscle contraction to recruit more muscle fibers when training: warming up or recovering. The Portable Electro-Stimulation Therapy Device stimulates nerve fibers by means of electrical impulses transmitted by electrical pulses generated by the Portable Electro-Stimulation Therapy Device stimulate motor nerves to stimulate a muscular response. Depending on the parameters of the electrical impulses (pulse frequency, duration of contraction, duration of rest, and total session duration), different types of muscle work can be imposed on the stimulated muscles. The Portable Electro-Stimulation Therapy Device may therefore be considered a technique of muscle training.

AI/ML Overview

This document is a 510(k) Premarket Notification from Guangzhou Longest Science & Technology Co., Ltd. for their Portable Electro-Stimulation Therapy Device, model LGT-231. The notification seeks to establish substantial equivalence to a predicate device (Compex Sport Elite, K170918) and therefore does not contain acceptance criteria or study data in the way a clinical trial or performance study for a novel device would. Instead, it focuses on demonstrating that the device meets safety and performance standards equivalent to the predicate device.

Based on the provided information, here's a breakdown:

1. Table of Acceptance Criteria and Reported Device Performance

The document does not explicitly present "acceptance criteria" for a specific performance metric of the device in a comparative study against a clinical endpoint. Instead, the "acceptance criteria" are implied by demonstrating equivalence to a predicate device and adherence to recognized standards. The "reported device performance" is presented as its technical specifications and compliance with those standards, rather than clinical outcomes.

Here's a table summarizing the comparison to the predicate device, highlighting where the subject device "meets" or is considered "similar" to the predicate, thus satisfying the substantial equivalence requirement.

Characteristic	Subject Device (LGT-231)	Predicate Device (Compex Sport Elite)	Discussion of Difference/Equivalence
General Characteristics
Classification	21 CFR 890.5850, 21 CFR 882.5890	21 CFR 890.5850, 21 CFR 882.5890	Same
Prescription/OTC	OTC	OTC	Same
Product Code	NGX, NUH, NYN	NGX, NUH, NYN	Same
FDA Class	II	II	Same
Intended Use	NMES: stimulate healthy muscles to improve/facilitate muscle performance. TENS: temporary relief of pain associated with sore/aching muscles, symptomatic relief/management of chronic, intractable pain, and arthritis pain relief. For adults only.	NMES: stimulate healthy muscles to improve/facilitate muscle performance. TENS: temporary relief of pain associated with sore/aching muscles, symptomatic relief/management of chronic, intractable pain, and arthritis pain relief. For adults only.	Same (Minor wording differences, but identical indications)
Target Population	Adults	Adults	Same
Power Source	Rechargeable lithium battery 3.7V	Rechargeable Ni-Mh Battery 4.8V	Similar: "The proposed device was demonstrated electromagnetic compatibility and electrical safety by the testing. The difference does not raise the issue of product's safety and effectiveness."
Method of Line Current Isolation	N/A (battery operated device)	N/A (battery operated device)	Same
Patient Leakage Current (Normal)	N/A (battery operated device)	N/A (battery operated device)	Similar: "The proposed device was demonstrated electrical safety by passing ANSI AAMI ES60601-1 and IEC 60601-2-10 tests. The difference does not raise the issue of product's safety and effectiveness."
Patient Leakage Current (Single Fault)	N/A (battery operated device)	N/A (battery operated device)	Same
Number of Output Channels	Two	Four	Different: "More channels means it can be applied on more different body sides at the same time, and all output channel works independently from each other, the proposed device has less channels than equivalent device, this can be addressed by applied two proposed device, therefore, the different channel number will not affect the safety and effectiveness of the proposed device."
Synchronous or Alternating?	Synchronous	Synchronous	Same
Method of Channel Isolation	Isolating transformer	Each channel is the middle of a H-Bridge.	Similar: "The proposed device was demonstrated electrical safety by passing ANSI AAMI ES60601-1 and IEC 60601-2-10 tests. The difference in Method of Channel Isolation does not raise the issue of product's safety and effectiveness."
Number of Output Modes	Two (TENS and NMES)	Two (TENS and NMES)	Same
Regulated Current or Voltage?	Current	Current	Same
Software/Firmware/Microprocessor Control?	Yes	Yes	Same
Automatic Overload Trip?	Yes	Yes	Same
Automatic No-Load Trip?	Yes	Yes	Same
Automatic Shut Off?	"On/Off" button	"On/Off" switch	Same
User Override Control?	Yes	Yes	Same
Indicator: On/Off Status?	Yes	Yes	Same
Display: Low Battery?	Yes	Yes	Same
Display: Voltage/Current Level?	Yes (on app)	Yes	Same: "System validation testing scenarios covering mitigation of wireless risks in accordance with RED were added to our full system testing protocol to ensure safe and effective use."
Timer Range (minutes)	Maximum = 60 minute	Maximum = 55 minute	Different: "The treatment time is adjusted by the user or depend on selected programs, so the difference doesn't affect the safety and effectiveness of the proposed device."
Compliance with 21 CFR 898?	Yes	Yes	Same
ANSI AAMI ES60601-1	Yes	Yes	Same
IEC 60601-2-10	Yes	Yes	Same
Weight	120g (only main unit)	300 g	Different: "The Weight will not affect the safety and effectiveness of the proposed device."
Dimensions (mm) (W x H x D)	62 (W) × 122 (L) × 27 (H) (mm)	99 x 142 x 36 (mm)	Different: "The dimensions will not affect the safety and effectiveness of the proposed device."
Housing Materials and Construction	Casing: Plastic (PC+ABS, with PMMA on button panel). Buttons: ABS. Light pipe: PC	Casing: Plastic (ABS, with PMMA on windows). Buttons: Silicon, rubber. Battery Pack: Rigid, ABS housing. Battery contacts: SK5 steel.	Similar: "The Housing Materials and Construction form the basic construction and ensure the basic safety of device, since the proposed device was demonstrated electrical safety by passing ANSI AAMI ES60601-1 and IEC 60601-2-10 tests, the existed difference will not affect the safety of the proposed device."
Programs	NMES: (not detailed). TENS: Normal, Sweep, Random, Alternation (different frequency modulation methods).	NMES: Endurance, Resistance, Strength, Explosive Strength, Potentiation, Training Recovery, Competition Recovery, Pre-Warmup Program, Muscle Relaxation. TENS: Pain relief TENS (same as FM).	Similar: "The two devices have two same main Output Modes: NMES and TENS, both modes NMES and TENS of these two devices also have same indications respectively, although both modes have different output programs, these two modes have almost the same parameter range, and the NMES of the proposed device can be adjusted arbitrarily within the parameter range, the TENS output programs: Normal, Sweep, Random, Alternation represents different frequency adjustment methods, same as Frequency Modulation which is same with the equivalent device. Therefore, the existed difference will not affect the safety and effectiveness of the proposed device."
Output Specifications
Waveform	NMES: Symmetrical biphasic. TENS: Balanced Symmetrical biphasic (Normal, Random, Sweep, Alternation).	NMES: Symmetrical Biphasic (all programs). TENS: Balanced, asymmetrical Biphasic (Pain relief TENS).	Same (for NMES), Similar (for TENS, although stated as 'Same' in the table row, the text mentions "Balanced, asymmetrical Biphasic" for predicate TENS vs "Balanced Symmetrical biphasic" for subject TENS, this is not fully articulated in the discussion, but generally within a range expected not to raise new questions.)
Shape	NMES: Rectangular. TENS: Rectangular (all modes).	NMES: Rectangular (all programs). TENS: Rectangular (Pain relief TENS).	Same
Maximum Output Voltage (± 10%)	NMES: 50V @ 500Ω, 115V @ 2kΩ, 125V @ 10kΩ. TENS: Similar values for all modes.	NMES: 60V @ 500Ω, 165V @ 2kΩ, 165V @ 10kΩ. TENS: Similar values for Pain Relief TENS.	Similar: "The max output voltage of proposed device is smaller than predicate device, the predicate device is safe and effective with its output voltage range which means the proposed device is also safe and effective with its output voltage, and at the meantime, the proposed device was also demonstrated electrical safety by passing ANSI AAMI ES60601-1 and IEC 60601-2-10 tests. Therefore, the difference does not raise the issue of product's safety and effectiveness."
Maximum Output Current (± 10%)	NMES: 100mA @ 500Ω, 58mA @ 2kΩ, 13mA @ 10kΩ. TENS: Similar values for all modes.	NMES: 120mA @ 500Ω, 82mA @ 2kΩ, 16mA @ 10kΩ. TENS: Similar values for Pain Relief TENS.	Similar: "The output current of proposed device is smaller than predicate device, the predicate device is safe and effective with its output current range which means the proposed device is also safe and effective with its output current, and at the meantime, the proposed device was also demonstrated electrical safety by passing ANSI AAMI ES60601-1 and IEC 60601-2-10 tests. Therefore, the difference does not raise the issue of product's safety and effectiveness."
Pulse Width	NMES: 50 to 400 µs. TENS: 50 to 400 µs (all modes).	NMES: 200 to 400 [µs] (all programs). TENS: 70 to 300[µs].	Similar: "Risk arises with larger Pulse Width, since the largest Pulse Width of proposed device is same the predicate device, this tiny differences will not affect the safety and effectiveness of the proposed device."
Frequency	NMES: 1 to 120 Hz. TENS: 1 to 120 Hz (all modes).	NMES: 1 to 100 Hz (most programs). TENS: 5 to 122 Hz.	Similar: "The different frequency will finally cause different feelings, as for NMES mode, the frequency range of the proposed device is 1~~120Hz and the equivalent device is 1~~100Hz, both of them have similar frequency range and the parameter of the proposed device can be adjusted to the same with the proposed device, as for TENS mode, the frequency range of the proposed device is 1~~120Hz, and the equivalent device is 5~~122Hz, both of them have similar frequency range and are Frequency Modulation, therefore, these tiny difference existed in Frequency between proposed device and predicate device are acceptable. The difference will not raise the issue of product's safety and effectiveness."
Symmetrical phases?	Yes	Yes	Same
Phase Duration	NMES: Symmetrical, 50 - 400 µs. TENS: Symmetrical, 50 - 400 µs.	NMES: Symmetrical, 280 - 400 µs. TENS: Symmetrical, 70 - 300 µs.	Similar: "Risk arises with larger Pulse Width, since the largest Pulse Width of proposed device is same the predicate device, this tiny differences will not affect the safety and effectiveness of the proposed device."
Net Charge (µC/pulse)	NMES: 0 μC @ 500Ω. TENS: 0 μC @ 500Ω.	NMES: 0 [μC] @ 500Ω (Excitation pulse fully Compensated). TENS: 0 [μC] @ 500Ω (Excitation pulse fully compensated).	Same
Maximum Phase Charge (µC)	NMES: 48.24 μC @ 500Ω. TENS: 46.73 μC @ 500Ω.	48 (μC) @ 500Ω.	Similar: "The tiny difference existed in Maximum Phase Charge between proposed device and predicate device are acceptable and the proposed device was demonstrated electrical safety by passing ANSI AAMI ES60601-1 and IEC 60601-2-10 tests. The difference does not raise the issue of product's safety and effectiveness."
Maximum Current Density (mA/cm², r.m.s.)	TENS: 1.94mA/cm² @ 500Ω. NMES: 2.00mA/cm² @ 500Ω.	4.8 (mA/cm²) @ 500Ω.	Similar: "The proposed device has a smaller maximum current density than predicate device. The proposed device was also demonstrated electrical safety by passing ANSI AAMI ES60601-1 and IEC 60601-2-10 tests. The difference does not raise the issue of product's safety and effectiveness."
Maximum Average Power Density (mW/cm²)	TENS: 30.15 mW/cm² @500Ω. NMES: 32.28 mW/cm² @500Ω.	27.6 (mW/cm²) @500Ω.	Similar: "The tiny difference existed in Maximum Average Power between proposed device and predicate device are acceptable and the proposed device was demonstrated electrical safety by passing ANSI AAMI ES60601-1 and IEC 60601-2-10 tests. The difference does not raise the issue of product's safety and effectiveness."
Burst Mode	N/A, no burst mode	N/A, no burst mode	Same
ON Time (seconds)	Depends on user settings.	Depends on selected program.	Same: "Both device is depended on the user's selection."
OFF Time (seconds)	Depends on user settings 1-60min.	Depends on selected program.	Same: "Both device is depended on the user's selection."

2. Sample size used for the test set and the data provenance:

Test Set Sample Size: The document does not describe any clinical test set involving human subjects to evaluate the device's therapeutic effectiveness. The non-clinical testing involved various electrical, mechanical, and software tests to demonstrate compliance with standards and equivalence to the predicate device.
Data Provenance: Not applicable, as there isn't a clinical test set in the traditional sense for this 510(k) submission. The testing performed was non-clinical (bench testing, software verification) by the manufacturer in China.

3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts:

Not applicable. This 510(k) submission did not involve a clinical study requiring human experts to establish ground truth for a test set of data. The ground truth for the non-clinical tests was established by the technical specifications of the device and the requirements of the international safety and performance standards.

4. Adjudication method (e.g., 2+1, 3+1, none) for the test set:

Not applicable. There was no clinical test set requiring adjudication.

5. If a multi-reader multi-case (MRMC) comparative effectiveness study was done, If so, what was the effect size of how much human readers improve with AI vs without AI assistance:

Not applicable. This device is not an AI-powered diagnostic imaging system or similar technology that would involve human readers or AI assistance in interpretation. It is an electro-stimulation therapy device.

6. If a standalone (i.e., algorithm only without human-in-the-loop performance) was done:

Not applicable. This refers to the performance of an algorithm without human intervention, typically for AI/ML-based devices. This device is a hardware electro-stimulation therapy device, not an algorithm.

7. The type of ground truth used (expert consensus, pathology, outcomes data, etc.):

For the non-clinical tests, the "ground truth" was based on:
- Technical Specifications: The declared specifications of the device itself.
- International Standards: Requirements defined by standards such as ISO 10993-5, ISO 10993-10, ANSI AAMI ES60601-1, ANSI AAMI ES60601-1-2, IEC 60601-2-10, and ANSI AAMI ES60601-1-11.
- Predicate Device Specifications: The established safety and performance characteristics of the legally marketed predicate device (Compex Sport Elite, K170918).

8. The sample size for the training set:

Not applicable. This device does not use machine learning or AI that would require a "training set" of data.

9. How the ground truth for the training set was established:

Not applicable, as there is no training set for this type of device.

Summary of the Study that Proves the Device Meets Acceptance Criteria:

The document states that non-clinical verification testing was performed to demonstrate that the Portable Electro-Stimulation Therapy Device, model: LGT-231 meets its design specifications and is suitable for its intended use. This testing established that the device is as safe, as effective, and performs as well as the predicate device (Compex Sport Elite, K170918), and that no new issues of safety and effectiveness were raised.

The "study" or evidence provided includes:

Comparison to a Predicate Device (K170918 Compex Sport Elite): Detailed tables comparing the technological characteristics and output specifications of the subject device to the predicate device. For each difference identified, a discussion is provided to argue why the difference "does not raise the issue of product's safety and effectiveness" or why the devices are "similar" or "same."
Compliance with International Standards: The device underwent testing to demonstrate compliance with a list of recognized consensus standards:
- ISO 10993-5:2009 (Biological evaluation - Cytotoxicity)
- ISO 10993-10:2010 (Biological evaluation - Irritation and skin sensitization)
- ANSI AAMI ES60601-1:2005+A1:2012 (Medical electrical equipment - General requirements for basic safety and essential performance)
- ANSI AAMI ES60601-1-2:2014 (Medical electrical equipment - Electromagnetic compatibility)
- IEC 60601-2-10:2012 (Particular requirements for the safety of nerve and muscle stimulators)
- ANSI AAMI ES60601-1-11:2015 (Medical electrical equipment - Home healthcare environment)
Internal Verification and Validation: The document states the device was "designed, verified, and validated according to the company's Design Control process and has been subjected to extensive safety and performance testing."

Conclusion from the Submission:

The manufacturer concluded that "bench and non-clinical testing were sufficient to demonstrate that Portable Electro-Stimulation Therapy Device, model: LGT-231 is as safe and effective as the predicate device." The electrical safety, EMC, biocompatibility, software verification and validation, basic unit characteristics, and output specifications information were deemed sufficient to demonstrate substantial equivalence. Given the "nearly identical" nature and "essentially identical technological characteristics" with identical indications for use, the device was found substantially equivalent to the Compex Sport Elite.

Summary

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Image /page/0/Picture/0 description: The image shows the logo for the U.S. Food & Drug Administration (FDA). On the left is the Department of Health & Human Services logo. To the right of that is the FDA logo in blue. Underneath the FDA logo is the word "ADMINISTRATION".

September 17, 2020

Guangzhou Longest Science & Technology Co., Ltd. % You Yiiie Manager Oimmig Medical Consulting Service Co., Ltd RM.1711, Building K, NO.101 Science Ave International Creative Valley Guangzhou, 510663 Cn

Re: K182020

Trade/Device Name: Portable Electro-Stimulation Therapy Device Regulation Number: 21 CFR 890.5850 Regulation Name: Powered Muscle Stimulator Regulatory Class: Class II Product Code: NGX, NUH, NYN Dated: July 27, 2020 Received: July 27, 2020

Dear You Yijie:

We have reviewed your Section 510(k) premarket notification of intent to market the device referenced above and have determined the device is substantially equivalent (for the indications for use stated in the enclosure) to legally marketed predicate devices marketed in interstate commerce prior to May 28, 1976, the enactment date of the Medical Device Amendments, or to devices that have been reclassified in accordance with the provisions of the Federal Food, Drug, and Cosmetic Act (Act) that do not require approval of a premarket approval application (PMA). You may, therefore, market the device, subject to the general controls provisions of the Act. Although this letter refers to your product as a device, please be aware that some cleared products may instead be combination products. The 510(k) Premarket Notification Database located at https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfpmn/pmn.cfm identifies combination product submissions. The general controls provisions of the Act include requirements for annual registration, listing of devices, good manufacturing practice, labeling, and prohibitions against misbranding and adulteration. Please note: CDRH does not evaluate information related to contract liability warranties. We remind you, however, that device labeling must be truthful and not misleading.

If your device is classified (see above) into either class II (Special Controls) or class III (PMA), it may be subject to additional controls. Existing major regulations affecting your device can be found in the Code of Federal Regulations, Title 21, Parts 800 to 898. In addition, FDA may publish further announcements concerning your device in the Federal Register.

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Please be advised that FDA's issuance of a substantial equivalence determination does not mean that FDA has made a determination that your device complies with other requirements of the Act or any Federal statutes and regulations administered by other Federal agencies. You must comply with all the Act's requirements, including, but not limited to: registration and listing (21 CFR Part 807); labeling (21 CFR Part 801); medical device reporting of medical device-related adverse events) (21 CFR 803) for devices or postmarketing safety reporting (21 CFR 4, Subpart B) for combination products (see https://www.fda.gov/combination-products/guidance-regulatory-information/postmarketing-safety-reportingcombination-products); good manufacturing practice requirements as set forth in the quality systems (QS) regulation (21 CFR Part 820) for devices or current good manufacturing practices (21 CFR 4, Subpart A) for combination products; and, if applicable, the electronic product radiation control provisions (Sections 531-542 of the Act); 21 CFR 1000-1050.

Also, please note the regulation entitled, "Misbranding by reference to premarket notification" (21 CFR Part 807.97). For questions regarding the reporting of adverse events under the MDR regulation (21 CFR Part 803), please go to https://www.fda.gov/medical-device-safety/medical-device-reportingmdr-how-report-medical-device-problems.

For comprehensive regulatory information about medical devices and radiation-emitting products, including information about labeling regulations, please see Device Advice (https://www.fda.gov/medicaldevices/device-advice-comprehensive-regulatory-assistance) and CDRH Learn (https://www.fda.gov/training-and-continuing-education/cdrh-learn). Additionally, you may contact the Division of Industry and Consumer Education (DICE) to ask a question about a specific regulatory topic. See the DICE website (https://www.fda.gov/medical-device-advice-comprehensive-regulatoryassistance/contact-us-division-industry-and-consumer-education-dice) for more information or contact DICE by email (DICE@fda.hhs.gov) or phone (1-800-638-2041 or 301-796-7100).

Sincerely.

Vivek Pinto, PhD Director DHT5B: Division of Neuromodulation and Physical Medicine Devices OHT5: Office of Neurological and Physical Medicine Devices Office of Product Evaluation and Quality Center for Devices and Radiological Health

Enclosure

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Indications for Use

510(k) Number (if known) K182020

Device Name

Portable Electro-Stimulation Therapy Device, model LGT-231

Indications for Use (Describe)

Portable Electro-Stimulation Therapy Device, model LGT-231 is to be used by adults only and has two modes NMES, TENS.

NMES is used to: stimulate healthy muscles in order to improve or facilitate muscle performance.

TENS is used to:

Temporary relief of pain associated with sore and aching muscles due to strain from exercise or normal household and work activities.
Symptomatic relief and management of chronic, intractable pain associated with arthritis.

Type of Use (Select one or both, as applicable)
-------------------------------------------------	--

| | Prescription Use (Part 21 CFR 801 Subpart D)

|X | Over-The-Counter Use (21 CFR 801 Subpart C)

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510(K) Summary

1. Submitter's Information

Establishment Registration Information

Name: Guangzhou Longest Science & Technology Co., Ltd. Address: 5&6f, Building B4, No.11, Kaiyuan Avenue Science City, Hi-Tech Industrial Zone, Guangzhou, Guangdong CHINA

Contact Person of applicant

Name: Xiaobing Luo Address: 5&6f, Building B4, No.11, Kaiyuan Avenue Science City, Hi-Tech Industrial Zone Guangzhou, Guangdong CHINA TEL: +86 020-66353999 FAX: +86 020-66353999 Email: gzlongest@126.com

Contact Person of the Submission:

Name: You Yijie Address: RM.1711, Building K, NO.101 Science Ave International Creative Valley Development Zone, Guangzhou China TEL: +86 020-8224 5821 FAX: +86 020-8224 5821 Email: Jet.you@qimmiq-med.com

Contact Person to prepare summary:

Name: You Yijie Address: RM.1711, Building K, NO.101 Science Ave International Creative Valley Development Zone, Guangzhou China TEL: (+86) 020-8224 5821 FAX: (+86) 020-8224 5821 Email: Jet.you@qimmiq-med.com Date to prepare: 7/5/2018

2. Device Information

Type of 510(K) submission: Traditional Trade Name: Portable Electro-Stimulation Therapy Device Model: LGT-231 Requlation name: Powered muscle stimulator. Transcutaneous electrical nerve stimulator for pain relief. Review panel: Physical Medicine, Neurology Product code: NGX, NUH, NYN Regulation Class: II Regulation Number: 21 CFR 890.5850, 21 CFR 882.5890

3. Predicate Device Information

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510(k) submitter/holder:	DJO, LLC
510(K) Number:	K170918
Device:	Compex Sport Elite
Trade name:	Compex Sport Elite
Regulation name:	Powered muscle stimulator. Transcutaneous electrical nerve stimulator for pain relief.
Review panel:	Physical Medicine, Neurology
Product code:	NGX, NUH, NYN
Regulation Class:	II
Regulation Number:	21 CFR 890.5850, 21 CFR 882.5890

4. Device description

The main unit provides access to adjust the intensity up or down, put ON/OFF the main unit.

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therefore be considered a technique of muscle training.

5. Principle of operation:

The Portable Electro-Stimulation Therapy Device, model LGT-231 sends gentle electrical current to underlying nerves and muscle group via electrodes applied on the skin and powered by rechargeable lithium battery. When used in TENS mode, it is specifically targets the sensory nerves, which are responsible for sending pain signals to the brain; and it uses tiny electrical impulses sent through the skin to nerves to modify the pain perception and finally helps control the pain. IN NMES mode. Portable Electro-Stimulation Therapy Device stimulates nerve fibers by means of electrical impulses transmitted by electrodes, the electrical pulses generated by the Portable Electro-Stimulation Therapy Device stimulate motor nerves to stimulate a muscular response and to create a muscle contraction to recruit more muscle fibers when training.

6. Indications for Use

Portable Electro-Stimulation Therapy Device, model LGT-231 is to be used by adults only and has two modes NMES and TENS.

NMES is used to: stimulate healthy muscles in order to improve or facilitate muscle performance.

TENS is used to:

Temporary relief of pain associated with sore and aching muscles due to strain from exercise or normal household and work activities.
Symptomatic relief and management of chronic, intractable pain and relief of pain associated with arthritis.

7. Summary of technological characteristics of device compared to the predicate devices (K170918)

Characteristic	Subject devicePresent application(PortableElectro-StimulationTherapy Device, modelLGT-231)	Predicate device(K170918, CompexSport Elite)	Discussion of difference
Manufacturer	Guangzhou LongestScience & TechnologyCo., Ltd	DJO, LLC	/
Picture	Image: Portable Electro-Stimulation Therapy Device, model LGT-231	Image: Compex Sport Elite	/
Classification		21 CFR 890.5850,21 CFR 882.5890	21 CFR 890.5850,21 CFR 882.5890	Same
Prescription/OTC		OTC	OTC	Same
Product Code		NGX, NUH, NYN	NGX, NUH, NYN	Same
FDA Class		II	II	Same
Intended Use		PortableElectro-StimulationTherapy Device, modelLGT-231 is to be used byadults only and has twomodes NMES and TENS.NMES is used to: stimulatehealthy muscles in order toimprove or facilitate muscleperformance.TENS is used to:1. Temporary relief of painassociated with sore andaching muscles due tostrain from exercise ornormal household andwork activities.2. Symptomatic relief andmanagement of chronic,intractable pain and reliefof pain associated witharthritis.	NMES: The Compex SportElite is intended tostimulate healthy musclesin order to improve orfacilitate muscleperformance. The workimposed on the muscles bythe Compex Sport Eliteprograms is not suitable forrehabilitation orphysiotherapy.TENS: The Compex SportElite TENS is intended for:• Temporary relief of painassociated with sore andaching muscles due tostrain from exercise ornormal household andwork activities• They symptomatic reliefand management ofchronic, intractable painand relief of painassociated with arthritis.The Compex® Sport Eliteis an Over-The-Counterdevice to be used by adultsonly.	Same
target population		adults	adults	Same
Power Source		Rechargeable lithiumbattery 3.7V	Rechargeable Ni-MhBattery 4.8V	SimilarThe proposed device wasdemonstrated electromagneticcompatility and electrical safetyby the testing. The differencedoes not raise the issue ofproduct's safety andeffectiveness.
Method of linecurrent isolation		N/A (battery operateddevice)	N/A (battery operateddevice)	Same
PatientLeakageCurrent	Normalcondition	N/A (battery operateddevice)	N/A (battery operateddevice)	SimilarThe proposed device wasdemonstrated electrical safety bypassing ANSI AAMI ES60601-1and IEC 60601-2-10 tests. Thedifference does not raise theissue of product's safety andeffectiveness.
	Single faultcondition	N/A (battery operateddevice)	N/A (battery operateddevice)	Same
Numberof OutputChannels	Number	Two	Four	Different
				More channels means it can beapplied on more different bodysides at the same time, and alloutput channel worksindependently from each other,the proposed device has lesschannels than equivalent device,this can be addressed by appliedtwo proposed device, therefore,the different channel number willnot affect the safety andeffectiveness of the proposeddevice.
SynchronousorAlternating?		Synchronous	Synchronous	Same
Method ofChannelIsolation		Isolating transformer	Each channel is the middleof a H-Bridge. Except whenit is activated, eachchannel is always in highimpedance state.	SimilarThe proposed device wasdemonstrated electrical safety bypassing ANSI AAMI ES60601-1and IEC 60601-2-10 tests. Thedifference in Method of ChannelIsolation does not raise the issueof product's safety andeffectiveness.
Number of OutputModes		Two (TENS and NMES)	two (TENS and NMES)	Same
Regulated Current orRegulated Voltage?		Current	Current	Same
Software/Firmware/Microprocessor Control?		Yes	Yes	Same
Automatic Overload Trip?		Yes	Yes	Same
Automatic No-LoadTrip?		Yes	Yes	Same
Automatic Shut Off?		"On/Off" button	"On/Off" switch	Same
User Override Control?		Yes	Yes	Same
Indicator	On/Off Status?	Yes	Yes	Same
Display	Low Battery?	Yes	Yes	Same
	Voltage/ CurrentLevel?	Yes (on app)	Yes	SameSystem validationtesting scenarioscovering mitigation ofwireless risks inaccordance withRED were added to our fullsystem testing protocol to ensuresafe and effective use.
Timer Range(minutes)		Maximum = 60 minute	Maximum = 55 minute	DifferentThe treatment time is adjusted bythe user or depend on selectedprograms, so the difference doesn'taffect the safety and effectivenessof the proposed device.
	Compliance with 21 CFR898?	Yes	Yes	Same
	ANSI AAMI ES60601-1	Yes	Yes	Same
IEC 60601-2-10	Yes	Yes	Same
Weight	120g (only main unit)	300 g	DifferentThe Weight will not affect thesafety and effectiveness of theproposed device
Dimensions (mm)(W x H x D)	62 (W) × 122 (L) × 27 (H)(mm)	99 x 142 x 36 (mm)3.9 x 5.6 x 1.4 (in)	DifferentThe dimensions will not affect thesafety and effectiveness of theproposed device
Housing Materials andConstruction	Casing: Plastic (PC+ABS,with PMMA on the buttonpanel)Buttons: ABSLight pipe: PC	Casing:Plastic (ABS, with PMMAon the windows)Buttons:Silicon, rubberBattery Pack:Rigid, ABS housingaround the batterycellsBattery contacts:SK5 steel	SimilarThe Housing Materials andConstruction form the basicconstruction and ensure the basicsafety of device, since theproposed device wasdemonstrated electrical safety bypassing ANSI AAMI ES60601-1and IEC 60601-2-10 tests, theexisted difference will not affectthe safety of the proposed device.
Programs	NMES:TENS:- Normal- Sweep- Random- Alternation representsdifferent frequencymodulation methods)	NMES:- Endurance- Resistance- Strength- Explosive Strength- Potentiation- Training Recovery(same as ActiveRecovery)- CompetitionRecovery (same asRecovery Plus)- Pre-WarmupProgram- Muscle Relaxation(same as Massage)TENS:-Pain relief TENS(same as FM)	SimilarThe two devices have two samemain Output Modes: NMES andTENS, both modes NMES andTENS of these two devices alsohave same indicationsrespectively, although bothmodes have different outputprograms, these two modes havealmost the same parameterrange, and the NMES of theproposed device can be adjustedarbitrarily within the parameterrange, the TENS outputprograms: Normal, Sweep,Random, Alternation representsdifferent frequency adjustmentmethods, same as FrequencyModulation which is same withthe equivalent device. Therefore,the existed difference will notaffect the safety and effectivenessof the proposed device.

Basic Device Characteristics - Comparison with Predicate Device

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Output Specifications – Comparison with Predicate Device

Characteristic	Subject devicePresent application(PortableElectro-StimulationTherapy Device, modelLGT-231)	Predicate device(K170918, Compex SportElite)	Discussion of difference
Manufacturer	Guangzhou LongestScience & TechnologyCo., Ltd	DJO, LLC	/

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Waveform	NMES:	NMES:	Same
	Symmetrical biphasic	-Endurance:Symmetrical Biphasic
	TENS:- Normal:Balanced Symmetricalbiphasic	-Resistance:Symmetrical Biphasic
	- Random:Balanced Symmetricalbiphasic	-Strength:Symmetrical Biphasic
	- Sweep:Balanced Symmetricalbiphasic	-Explosive Strength:Symmetrical Biphasic
	- AlternationBalanced Symmetricalbiphasic	-Potentiation:Symmetrical Biphasic
		-Training Recovery (sameas Active Recovery):Symmetrical Biphasic
		-CompetitionRecovery (same asRecovery Plus):Symmetrical Biphasic
		-Pre-Warmup Program:Symmetrical Biphasic
		-Muscle Relaxation (sameas Massage):Symmetrical Biphasic
		TENS:-Pain relief TENS (sameas FM): Balanced,asymetricalBiphasic
Shape (e.g., rectangular,spike, rectified sinusoidal)	NMES:Rectangular	NMES:-Endurance:Rectangular	Same
	TENS:- Normal:Rectangular	-Resistance:Rectangular
	- Random:Rectangular	-Strength:Rectangular
	- Sweep:Rectangular	-Explosive Strength:Rectangular
	- AlternationRectangular	-Potentiation:Rectangular
		-Training Recovery(same as ActiveRecovery):Rectangular
		-Competition

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		Recovery (same as
		Recovery Plus):
		Rectangular
		-Pre-WarmupProgram: Rectangular
		-Muscle Relaxation(same as Massage):Rectangular
		TENS:-Pain relief TENS(same as FM): Rectangular
Maximum OutputVoltage (± 10%)	NMES:50 V @ 500 Ω115 V @ 2 kΩ125 V @ 10 kΩ	NMES:- Endurance:60 V @ 500 Ω165 V @ 2 kΩ165 V @ 10 kΩ	SimilarThe max output voltage ofproposed device is smaller thanpredicate device, the predicatedevice is safe and effective withits output voltage range whichmeans the proposed device isalso safe and effective with itsoutput voltage, and at themeantime, the proposed devicewas also demonstrated electricalsafety by passing ANSI AAMIES60601-1 and IEC 60601-2-10tests. Therefore, the differencedoes not raise the issue ofproduct's safety andeffectiveness.
	TENS:- Normal:50 V @ 500 Ω115 V @ 2 kΩ125 V @ 10 kΩ	- Resistance:60 V @ 500 Ω165 V @ 2 kΩ165 V @ 10 kΩ
	- Random:50 V @ 500 Ω115 V @ 2 kΩ125 V @ 10 kΩ	- Strength:60 V @ 500 Ω165 V @ 2 kΩ165 V @ 10 kΩ
	- Sweep:50 V @ 500 Ω115 V @ 2 kΩ125 V @ 10 kΩ	- Explosive Strength:60 V @ 500 Ω165 V @ 2 kΩ165 V @ 10 kΩ
	- Alternation50 V @ 500 Ω115 V @ 2 kΩ125 V @ 10 kΩ	- Potentiation:60 V @ 500 Ω152 V @ 2 kΩ136 V @ 10 kΩ
		- Training Recovery:60 V @ 500 Ω165 V @ 2 kΩ165 V @ 10 kΩ
		- Competition Recovery:60 V @ 500 Ω165 V @ 2 kΩ165 V @ 10 kΩ
				- Pre Warmup:60 V @ 500 Ω	60 V @ 500 Ω
		165 V @ 2 kΩ
		165 V @ 10 kΩ
		- Muscle Relaxation:
		60 V @ 500 Ω
		165 V @ 2 kΩ

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		165 V @ 10 kΩ

		TENS:
		- Pain Relief TENS:
		60 V @ 500 Ω
		152 V @ 2 kΩ
		165 V @ 10 kΩ
Maximum OutputCurrent (± 10%)	NMES:100 mA @ 500 Ω58 mA @ 2 kΩ	NMES:- Endurance:120 mA @ 500 Ω	Similar
	13 mA @ 10 kΩ	82 mA @ 2 kΩ	The output current of proposeddevice is smaller than predicate
		16 mA @ 10 kΩ	device, the predicate device is
	TENS:- Normal:	- Resistance:	safe and effective with its output
	100 mA @ 500 Ω	120 mA @ 500 Ω	current range which means the
	58 mA @ 2 kΩ	82 mA @ 2 kΩ	proposed device is also safe and
	13 mA @ 10 kΩ	16 mA @ 10 kΩ	effective with its output current,
			and at the meantime, the
	- Random:	- Strength:	proposed device was also
	100 mA @ 500 Ω	120 mA @ 500 Ω	demonstrated electrical safety by
	58 mA @ 2 kΩ	82 mA @ 2 kΩ	passing ANSI AAMI ES60601-1
	13 mA @ 10 kΩ	16 mA @ 10 kΩ	and IEC 60601-2-10 tests.
			Therefore, the difference does not
	- Sweep:100 mA @ 500 Ω	- Explosive Strength:120 mA @ 500 Ω	raise the issue of product's safety
	58 mA @ 2 kΩ	82 mA @ 2 kΩ	and effectiveness.
	13 mA @ 10 kΩ	16 mA @ 10 kΩ

	- Alternation	- Potentiation:
	100 mA @ 500 Ω	120 mA @ 500 Ω
	58 mA @ 2 kΩ	82 mA @ 2 kΩ
	13 mA @ 10 kΩ	16 mA @ 10 kΩ

		- Training Recovery:
		120 mA @ 500 Ω
		82 mA @ 2 kΩ16 mA @ 10 kΩ

		- Competition Recovery:
		120 mA @ 500 Ω
		82 mA @ 2 kΩ
		16 mA @ 10 kΩ

		- Pre Warmup
		120 mA @ 500 Ω
		82 mA @ 2 kΩ
		16 mA @ 10 kΩ

		- Muscle Relaxation:120 mA @ 500 Ω
		82 mA @ 2 kΩ
		16 mA @ 10 kΩ


		TENS:
		- Pain Relief TENS:
		119[mA] peak@500 Ω
		76[mA] peak@2 kΩ

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		12[mA] peak @10 kΩ
Pulse Width	NMES:50 to 400 µsTENS:- Normal:50 to 400 µs- Random:50 to 400 µs- Sweep:50 to 400 µs- Alternation50 to 400 µs	NMES:- Endurance:200 to 400 [µs]- Resistance:200 to 400 [µs]- Strength:200 to 400 [µs]- Explosive Strength:200 to 400 [µs]- Potentiation:200 to 400 [µs]- Training Recovery:200 to 400 [µs]- Competition Recovery:200 to 400 [µs]- Pre Warmup200 to 400 [µs]- Muscle Relaxation:200 to 400 [µs]TENS:- Pain Relief TENS:70 to 300[µs] (measured at 50% of positive pulse)	SimilarRisk arises with lager Pulse Width, since the largest Pulse Width of proposed device is same the predicate device, this tiny differences will not affect the safety and effectiveness of the proposed device
Frequency		NMES:1 to 120 HzTENS:- Normal:1 to 120 Hz- Random1 to 120 Hz- Sweep:1 to 120 Hz- Alternation1 to 120 Hz		NMES:- Endurance:10 Hz- Resistance:50 Hz- Strength:75 Hz- Explosive Strength:100 Hz- Potentiation:From 1 to 75 Hz- Training Recovery:10 Hz	- Competition Recovery:	SimilarThe different frequency will finally cause different feelings, as for NMES mode, the frequency range of the proposed device is 1~~120Hz and the equivalent device is 1~~100Hz, both of them have similar frequency range and the parameter of the proposed device can be adjusted to the same with the proposed device, as for TENS mode, the frequency range of the proposed device is 1~~120Hz, and the equivalent device is 5~~122Hz, both of them have similar frequency range and are Frequency Modulation, therefore, these tiny difference	existed in Frequency between
		0.5 Hz	proposed device and predicate
		- Pre Warmup:	device are acceptable. The
			difference will not raise the issue
			of product's safety and

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			4 Hz	effectiveness.
			- Muscle Relaxation:1 Hz
			TENS:- Pain Relief TENS:5 to 122Hz
For interferential modesonly:- Beat Frequency [Hz]		N/A	N/A	Same
Formultiphasic	Symmetricalphases?	Yes	Yes	Same
waveformsonly	PhaseDuration(includeunits)(state range,ifapplicable)(bothphases, ifasymmetrical)	NMES:Symmetrical, 50 -400 µs	NMES:- Endurance:Symmetrical, 280 -400 µs- Resistance:Symmetrical, 280 -400 µs- Strength:Symmetrical, 280 -400 µs- Explosive Strength:Symmetrical, 280 -400 µs- Potentiation:Symmetrical, 280 -400 µs- Training Recovery:Symmetrical, 280 -400 µs- CompetitionRecovery:Symmetrical, 280 -400 µs- Pre Warmup:Symmetrical, 280 -400 µs- Muscle Relaxation:Symmetrical, 280 -400 µsTENS:- Pain Relief TENS:Symmetrical, 70 -300 µs	SimilarRisk arises with lager PulseWidth, since the largest PulseWidth of proposed device is samethe predicate device, this tinydifferences will not affect thesafety and effectiveness of theproposed device
		TENS:- Normal:Symmetrical, 50 -400 µs- RandomSymmetrical, 50 -400 µs- Sweep:Symmetrical, 50 -400 µs- AlternationSymmetrical, 50 -400 µs
Net Charge (µC/pulse)		NMES:	NMES:	Same
	0 μC @ 500ΩTENS:- Normal:0 μC @ 500Ω	- Endurance:0 [μC] @ 500ΩExcitation pulse fullyCompensated
	- Random0 μC @ 500Ω	- Resistance:0 [μC] @ 500ΩExcitation pulse fullyCompensated
	- Sweep:0 μC @ 500Ω- Alternation0 μC @ 500Ω	- Strength:0 [μC] @ 500ΩExcitation pulse fullyCompensated
		- Explosive Strength:0 [μC] @ 500ΩExcitation pulse fullyCompensated
		- Potentiation:0 [μC] @ 500ΩExcitation pulse fullyCompensated
		- Training Recovery:0 [μC] @ 500ΩExcitation pulse fullyCompensated
		- Competition Recovery:0 [μC] @ 500ΩExcitation pulse fullyCompensated
		- Pre Warmup0 [μC] @ 500ΩExcitation pulse fullyCompensated
		- Muscle Relaxation:0 [μC] @ 500ΩExcitation pulse fullyCompensated
		TENS:- Pain Relief TENS:0 [μC] @ 500ΩExcitation pulse fullycompensated
Maximum Phase Charge(μC)	NMES:48.24 μC @ 500ΩTENS: 46.73 μC @ 500Ω	48 (μC) @ 500Ω	SimilarThe tiny difference existed inMaximum Phase Charge betweenproposed device and predicatedevice are acceptable and theproposed device wasdemonstrated electrical safety by
				and IEC 60601-2-10 tests. Thedifference does not raise theissue of product's safety andeffectiveness.
Maximum Current Density,(mA / cm², r.m.s.)	TENS: 1.94mA/cm² @500ΩNMES: 2.00mA/cm² @500Ω	4.8 (mA/cm²) @ 500Ω		SimilarThe proposed device has asmaller maximum current densitythan predicate device. Theproposed device was alsodemonstrated electrical safety bypassing ANSI AAMI ES60601-1and IEC 60601-2-10 tests. Thedifference does not raise theissue of product's safety andeffectiveness.
Maximum Average PowerDensity (mW/cm²)	TENS: 30.15 mW/cm²@500ΩNMES: 32.28 mW/cm²@500Ω	27.6 (mW/cm²) @500Ω		SimilarThe tiny difference existed inMaximum Average Powerbetween proposed device andpredicate device are acceptableand the proposed device wasdemonstrated electrical safety bypassing ANSI AAMI ES60601-1and IEC 60601-2-10 tests. Thedifference does not raise theissue of product's safety andeffectiveness.
BurstMode(i.e.,pulsetrains)	Pulses per burstBursts persecondBurst duration(seconds)Duty Cycle [Line(b) x Line (c)	N/A, no burst mode	N/A, no burst mode	Same
ON Time (seconds)		Depends on your ownsettings, Once started, theoutput is active until usermanually stops the unit	Depends on theselected program	SameBoth device is depended on theuser's selection
OFF Time (seconds)		Depends on your ownsettings 1-60min	Depends on theselected program	SameBoth device is depended on theuser's selection
Additional Features (ifapplicable)	N/A	N/A		Same

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8. Discussion of Non-Clinical Tests Performed for Determination of Substantial Equivalence are as follows:

Non-clinical verification testing of the Portable Electro-Stimulation Therapy Device, model: LGT-231 included electrical, mechanical, and software tests to show the device meets its design specifications. Validation and performance testing validates that the device meets its user needs. Verification and validation test results established that the device meets its intended use, that it is as safe, as effective, and performs as well as the predicate devices, and that no new issues of safety and effectiveness were raised. The Portable Electro-Stimulation Therapy Device, model: LGT-231 was designed, verified, and validated according to the company's Design Control process and has been subjected to extensive safety and performance testing as shown in the test results provided in this submission.

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Verification and Validation testing data demonstrate that the device meets all of its specifications including compliance with the following standards:

ISO 10993-5:2009 Biological evaluation of medical devices - Part 5: Tests for in vitro cvtotoxicitv

ISO 10993-10:2010 Biological evaluation of medical devices. Tests for irritation and skin sensitization

ANSI AAMI ES60601-1:2005+A1:2012 Medical electrical equipment. General requirements for basic safety and essential performance

ANSI AAMI ES60601-1-2:2014 Medical electrical equipment - part 1-2: general requirements for safety - collateral standard: electromagnetic compatibility - requirements and tests IEC 60601-2-10:2012 Medical Electrical equipment - Part 2-10: Particular requirements for the

safety of nerve and muscle stimulators

ANSI AAMI ES60601-1-11:2015 Medical electrical equipment - Part 1-11: General requirements for basic safety and essential performance - Collateral Standard: Requirements for medical electrical equipment and medical electrical systems used in the home healthcare environment.

9. Discussion of Clinical Tests Performed:

Longest determined that bench and non-clinical testing were sufficient to demonstrate that Portable Electro-Stimulation Therapy Device, model: LGT-231 is as safe and effective as the predicate device.

10. Conclusions

The electrical safety, EMC, biocompatibility, software verification and validation, basic unit characteristics, and output specifications information provided is sufficient to demonstrate substantial equivalence to the predicate device. As the Portable Electro-Stimulation Therapy Device, model: LGT-231 is nearly identical to the predicate device, differences in their characteristics do not raise any raise new questions regarding safety and effectiveness with identical indications for use and essentially identical technological characteristics, the Portable Electro-Stimulation Therapy Device, model: LGT-231 is substantially equivalent to the predicate device Compex Sport Elite.

Regulation Number and Section

§ 890.5850 Powered muscle stimulator.

(a)
Identification. A powered muscle stimulator is an electrically powered device intended for medical purposes that repeatedly contracts muscles by passing electrical currents through electrodes contacting the affected body area.(b)
Classification. Class II (performance standards).