The NeuroTrigger Basic (NTB) powered muscle stimulator is composed of a hardware component encased in Acrylonitrile Butadiene Styrene (ABS) plastic that attaches to the body with double-sided tape (DST) and delivers electrical stimulation to different body regions through a single use/disposable pre-gelled Y-shaped electrode. The Y-shaped electrodes consist of a PET base, with silver/silver chloride conductive ink, covered by a double coated medical polyethylene DST film, and hydrogel circles at the center of the Y heads.
The NTB System is made up of the following components and accessories:
Main components:

Stimulator
Electrodes
Android app
Accessories:
Stimulator holder, with double-sided adhesive stickers
Charging cradle
USB-C charge cable
AC/DC Charger
The NTB stimulator contains embedded software that controls the generation of the stimulation signals, provides current measurement circuitry to monitor the delivered current, provides a Bluetooth Low Energy (BLE) wireless communication with remote control SW running on Android based App. The electrical stimulation is delivered to different body regions through the 2 electrode sizes (either wide or narrow span electrodes). The stimulator is stored in the NTB charging cradle, the housing case for the device, when not in use. Both components (the stimulator and the cradle) are made of ABS, but the NTB stimulator contains a PCB board and a lithium battery, and fits into the cradle by magnetized coupling and is held in place with pogo pins. The cradle acts as a charging station for the stimulator in addition to being a housing storage unit. The cradle, built of two parts, contains magnets that allow for the single axis magnetic opening and closure of the case.
The AC/DC charger connects to the cradle through the USB C cable during charging cycles, which is when the stimulator is not in use.
The stimulator holder is supplied to allow for different body region uses, and is also made from ABS material and can be attached to different bodily regions with DST. The cradle and stimulator display different indications (i.e. BLE pairing, connection state, battery status) through LED lights.
NTB user setup is performed under the guidance and instruction of a supervising physician and is controlled wirelessly from the Android smartphone-based mobile application (Bluetooth connection to the stimulator). The stimulator contains embedded software that generates controllable stimulation signal for stimulating nerves and muscles. The stimulation signal parameters can be controlled by special application over Bluetooth Low Energy (BLE) connection. Communication with the stimulator host application is done over BLE, data are encrypted with the standard BLE pairing and encryption/decryption that is done at the BLE level.
The SW is a remote control application installed on portable Android device with support to BLE 4.2 and above to control the HW and serve as UI. Secured login mechanism is implemented on the application to prevent unsecured using of the application also to protect patient's personal information and details
The application supports three types of users:
Patients
Clinicians
Administrators
The SW is programmed to show the following LEDs/Display indications for general functions:
On/off
Low power
Effective electrode contact coupling
Application coupling

AI/ML Overview

The NeuroTrigger Basic (NTB) Device has the following acceptance criteria and device performance:

1. A table of acceptance criteria and the reported device performance:

Feature/Parameter	Acceptance Criteria (Predicate: Shenzhen XFT-2000)	Reported Device Performance (NeuroTrigger Basic)
Basic Unit Characteristics
Product Code	IPF, GZJ	IPF
Regulation Number	21 CFR 890.5850	21 CFR 890.5850
Intended Use	A powered muscle stimulator intended for medical purposes that repeatedly contracts muscles by passing electrical currents through electrodes contacting the affect body area.	A powered muscle stimulator intended for medical purposes that repeatedly contracts muscles by passing electrical currents through electrodes contacting the affect body area.
Indications for Use	XFT-2000 is intended for the following use: - Relaxation of muscle spasms - Prevention or retardation of disuse atrophy - Increasing local blood circulation - Muscle re-education - Immediate post-surgical stimulation of calf muscles to prevent venous thrombosis - Maintaining or increasing range of motion - Adjunctive treatment in the management of post-surgical and post-traumatic acute pain.	NeuroTrigger Basic is indicated for the prevention or retardation of disuse atrophy and muscle re-education to maintain or increase range of motion.
Technology	Electrical Muscle Stimulation (EMS)	Electrical Muscle Stimulation (EMS)
Power Source	N/A (battery operated)	N/A (battery operated)
Battery	3 AAA batteries	One rechargeable Lithium, Prismatic, 4.2V (3.7 nominal), 120 milliampere hour (mAh)
Average DC current through electrodes when device is on but no pulses are being applied	0 µA	0 µA
Number of Output Modes	1 mode for NMES, 1 mode for transcutaneous electrical nerve stimulation (TENS)	1 mode for neuromuscular stimulation (NMES)
Programs	- 10 pre-set NMES programs - 3 pre-set TENS programs - User can create and save custom programs - Frequency, pulse duration, amplitude, treatment time, and time on/off can be adjusted	- Unlimited number of programs can be created by the user - Frequency, pulse duration, amplitude, ramp up time, and time on/off can be adjusted
Number of Output Channels	2 channels	1 channel
Regulated current or voltage	Regulated current	Constant current (also referred to as regulated current)
Software / Firmware / Microprocessor Control?	Yes	Yes, software and firmware
Automatic overload trip?	Yes	Yes, if a zero load is connected, current shuts off
Automatic no-load trip?	Yes	Yes, if no load is connected, current shuts off
Automatic shut off	Yes	Yes
User override control?	Yes, pause button	Yes
Indicator Display: On / Off Status	Yes	Yes
Low Battery?	Yes	Yes
Voltage / Current Level?	Yes	Yes
Timer Range (min) (NMES mode)	60 min	Open Stimulation period (with a caution statement for max duration of 120 minutes)
Compliance with voluntary standards?	IEC 60601-1, IEC 60601-1-2, IEC 60601-2-10	IEC 60601-1, IEC 60601-1-2, IEC 60601-1-6, IEC 60601-1-11, IEC 60601-2-10, ISO 10993-1 Part 1
Compliance with 21 CFR 898?	Yes	Yes
Weight	96 g	11.9 g
Dimensions (mm)	114 x 66 x 20	65 x 60 x 13
Housing material	Silicone & ABS	ABS, injection molding
Stimulation Output Specifications
Waveform and shape	Pulsed, symmetric, balanced Biphasic, Rectangular	Pulsed, symmetric, balance biphasic, rectangular, with interphase interval
Area of electrode(s)	19.6 cm²	1.5 cm²
Dimensions of electrode(s)	5 cm diameter (round)	1.4 cm diameter (round)
Maximum output voltage @ 500 Ω ± 10%	29.7 V	12.5 V
Maximum output voltage @ 2 kΩ ± 10 %	89.1 V	50 V
Maximum output voltage @ 10 kΩ ± 10%	125 V	90 V (maximum voltage remains constant at a load larger than 3.6 kΩ)
Maximum output current @ 500 Ω ± 10 %	59.4 mA	25 mA
Maximum output current @ 2 kΩ ± 10%	44.5 mA	25 mA
Maximum output current @ 10 kΩ ± 10%	12.5 mA	9 mA
Maximum Phase Charge @ 500 Ω	10.8 µC	15.0 µC
Maximum Phase Charge @ 2 kΩ	15.6 µC	15.0 µC
Maximum Phase Charge @ 10KΩ	4.4 µC	5.4 µC
Pulse (phase) width	100 - 350 µs	80 - 600 µs
Frequency (Hz)	100-350 Hz	10 - 300 Hz
Net Charge (µC per pulse)	Zero (Biphasic, charge balanced stimulation)	Zero (Biphasic, charge balanced stimulation)
Maximum Power Density, (W/cm²) (using smallest electrode conductive surface area)	8.9 mW/cm² @ 500Ohm	19.1 mW/cm² @ 500Ohm
Max current (RMS) (mA) @ 500 Ω	16.9	7.57
Burst Mode - Pulses per burst	1 - 625 pulses	10 - 300 pulses
Burst Mode - Bursts per second	0.05 - 0.5 Hz	0.09 - 0.32 Hz
Burst Mode - Burst duration (s)	1 - 5 s	0.1 - 1.0 s
Burst Mode - Duty Cycle	Not available	0.9% - 32%
Connectivity	N/A	Bluetooth Low Energy (BLE 5.2) connectivity to Android platform-based app

Study Proving Acceptance Criteria:

The NeuroTrigger Basic (NTB) device's acceptance criteria are primarily met through performance testing that demonstrates its substantial equivalence to the predicate device, Shenzhen XFT-2000 (K193275), and compliance with relevant safety and performance standards. The provided document details a comprehensive set of non-clinical, bench tests to establish this.

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

Test Set Sample Size: The document does not specify a separate "test set" in terms of patient data or clinical trials. The evaluation relies on bench testing of the NeuroTrigger Basic device samples. The number of device units tested for each non-clinical test (e.g., biocompatibility, environmental, performance) is not explicitly stated, but it's implied that sufficient samples were used to meet testing standards.
Data Provenance: The data provenance is from non-clinical, bench testing conducted on the NeuroTrigger Basic device. There is no indication of retrospective or prospective clinical data from human subjects in this 510(k) summary. All testing appears to be laboratory-based.

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

This information is not applicable to this 510(k) submission. The "ground truth" for the non-clinical bench testing is defined by the recognized consensus standards (e.g., ISO, IEC, ASTM, FCC) that the device must comply with and the specified design performance parameters. The evaluation is based on whether the device's measured performance meets these established technical specifications and passes the standard-specific criteria, rather than expert interpretation of patient data.

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

This information is not applicable as the evaluation is based on objective, quantifiable measurements from bench testing against predefined standards and specifications, rather than subjective interpretation of clinical data 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:

This information is not applicable. The NeuroTrigger Basic is a powered muscle stimulator, not an AI-powered diagnostic or assistive device that would involve "human readers" or AI assistance in interpretation. No MRMC comparative effectiveness study was conducted.

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

This information is not applicable in the context of an "algorithm only" performance study. The NeuroTrigger Basic contains embedded software that controls stimulation signals and communicates with a mobile app. The performance of this software is assessed as part of the overall device performance in the bench testing (e.g., "Software verification and validation testing was conducted to test for the safe and secure use of the software with the NTB device, which included Bluetooth connection, stimulation parameter identification, and cybersecurity protection."). However, this is not a standalone "algorithm-only" performance study in the typical sense of AI-driven diagnostic tools.

7. The type of ground truth used:

The ground truth for evaluating the NeuroTrigger Basic device is based on:

Engineering design specifications: The device was tested to ensure conformance to its own design specifications.
Recognized consensus standards: Compliance with various international standards for medical electrical equipment (IEC 60601 series), biocompatibility (ISO 10993 series), and packaging/shelf-life (ASTM standards) serves as a primary ground truth.
Performance relative to a legally marketed predicate device: The concept of "substantial equivalence" means the device must perform similarly to or better than the predicate device without raising new questions of safety or effectiveness. The detailed comparison table and discussion of differences against the Shenzhen XFT-2000 serve as an indirect "ground truth" for functional equivalency.

8. The sample size for the training set:

This information is not applicable as there is no indication of a "training set" in the context of machine learning or AI algorithm development for this device. The software embedded in the device controls the stimulation signals and user interface, but it's not described as a learning algorithm requiring training data.

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

This information is not applicable as there is no training set described for this device.

Summary

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Image /page/0/Picture/0 description: The image shows the logo of the U.S. Food and Drug Administration (FDA). The logo consists of two parts: the Department of Health & Human Services logo on the left and the FDA logo on the right. The FDA logo features the letters "FDA" in a blue square, followed by the words "U.S. FOOD & DRUG ADMINISTRATION" in blue text.

October 10, 2023

NeuroTrigger Nikolai Kuincher CEO Nirim 3 Tel Aviv, Israel 67060 Israel

Re: K223027

Trade/Device Name: NeuroTrigger Basic (NTB) Regulation Number: 21 CFR 890.5850 Regulation Name: Powered Muscle Stimulator Regulatory Class: Class II Product Code: IPF Dated: September 23, 2022 Received: September 29, 2022

Dear Nikolai Kuincher:

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 (the 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 available 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.

Additional information about changes that may require a new premarket notification are provided in the FDA guidance documents entitled "Deciding When to Submit a 510(k) for a Change to an Existing Device" (https://www.fda.gov/media/99812/download) and "Deciding When to Submit a 510(k) for a Software Change to an Existing Device" (https://www.fda.gov/media/99785/download).

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Your device is also subject to, among other requirements, the Quality System (QS) regulation (21 CFR Part 820), which includes, but is not limited to, 21 CFR 820.30, Design controls; 21 CFR 820.90, Nonconforming product; and 21 CFR 820.100, Corrective and preventive action. Please note that regardless of whether a change requires premarket review, the QS regulation requires device manufacturers to review and approve changes to device design and production (21 CFR 820.30 and 21 CFR 820.70) and document changes and approvals in the device master record (21 CFR 820.181).

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 Part 803) for devices or postmarketing safety reporting (21 CFR Part 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 Part 4, Subpart A) for combination products; and, if applicable, the electronic product radiation control provisions (Sections 531-542 of the Act); 21 CFR Parts 1000-1050.

Also, please note the regulation entitled, "Misbranding by reference to premarket notification" (21 CFR 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 mediation-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,

Jitendra V. Virani -S

CDR Jitendra Virani Assistant 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

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Indications for Use

510(k) Number (if known) K223027

Device Name NeuroTrigger basic (NTB)

Indications for Use (Describe) Device Name: NeuroTrigger Basic

INDICATION FOR USE:

NeuroTrigger Basic is indicated for the prevention of disuse atrophy, muscle re-education, and for maintaining or increasing range of motion.

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

Prescription Use (Part 21 CFR 801 Subpart D)

[ ] Over-The-Counter Use (21 CFR 801 Subpart C)

CONTINUE ON A SEPARATE PAGE IF NEEDED.

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510K Summary

Submitter:

Submitter's Name	NeuroTrigger LTD
Address:	Nirim 3, Tel Aviv 67060, Israel
Phone	+972-52-296-3130
Contact Person Name:	Nikolai Kunicher, PhD
Title:	CEO
Phone Number:	+972-522963130
Dated:	September 27, 2023

Submitted Device:

Proprietary Name: NeuroTrigger Basic (NTB)

Common or Usual Name: Stimulator, power, muscle

Classification Name: Powered Muscle Stimulator

Product Code: IPF

Device Class: II

Review Panel: Physical Medicine

Regulation Number: 21 CFR 890.5850

Predicate Device: Shenzhen XFT-2000 (K193275)

Device Description:

The NTB System is made up of the following components and accessories:

Main components:

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Stimulator ●
Electrodes ●
Android app ●

Accessories:

Stimulator holder, with double-sided adhesive stickers ●
Charging cradle
USB-C charge cable ●
AC/DC Charger ●

The NTB stimulator contains embedded software that controls the generation of the stimulation signals, provides current measurement circuitry to monitor the delivered current, provides a Bluetooth Low Energy (BLE) wireless communication with remote control SW running on Android based App. The electrical stimulation is delivered to different body regions through the 2 electrode sizes (either wide or narrow span electrodes). The stimulator is stored in the NTB charging cradle, the housing case for the device, when not in use. Both components (the stimulator and the cradle) are made of ABS, but the NTB stimulator contains a PCB board and a lithium battery, and fits into the cradle by magnetized coupling and is held in place with pogo pins. The cradle acts as a charging station for the stimulator in addition to being a housing storage unit. The cradle, built of two parts, contains magnets that allow for the single axis magnetic opening and closure of the case.

The AC/DC charger connects to the cradle through the USB C cable during charging cycles, which is when the stimulator is not in use.

The stimulator holder is supplied to allow for different body region uses, and is also made from ABS material and can be attached to different bodily regions with DST. The cradle and stimulator display different indications (i.e. BLE pairing, connection state, battery status) through LED lights.

NTB user setup is performed under the guidance and instruction of a supervising physician and is controlled wirelessly from the Android smartphone-based mobile application (Bluetooth connection to the stimulator). The stimulator contains embedded software that generates controllable stimulation signal for stimulating nerves and muscles. The stimulation signal parameters can be controlled by special application over Bluetooth Low Energy (BLE) connection. Communication with the stimulator host application is done over BLE, data are encrypted with the standard BLE pairing and encryption/decryption that is done at the BLE level.

The SW is a remote control application installed on portable Android device with support to BLE 4.2 and above to control the HW and serve as UI. Secured login mechanism is implemented on the application to prevent unsecured using of the application also to protect patient's personal information and details

The application supports three types of users:

. Patients
Clinicians
. Administrators

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The SW is programmed to show the following LEDs/Display indications for general functions:

On/off -
-Low power
Effective electrode contact coupling -
Application coupling -

Indications for Use:

NeuroTrigger Basic is indicated for the prevention or retardation of disuse atrophy and muscle re-education to maintain or increase range of motion.

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Predicate Comparison Tables

Table 1: Basic Unit Characteristics (comparison with predicate device)

Device Name	NeuroTriggerBasic(Device UnderReview)	Shenzhen XFT-2000(Predicate Device)	Comparison
K number	K223027	K193275
Manufacturer	NeuroTrigger	Shenzhen XFT Medical Ltd.
Model number	NT-11	XFT-2000
Product code	IPF	IPF, GZJ	Same
Classification Name/Regulationnumber	21 CFR 890.5850	21 CFR 890.5850	Same
Intended Use	A powered muscle stimulator intendedfor medical purposes that repeatedlycontracts muscles by passingelectrical currents through electrodescontacting the affect body area.	A powered muscle stimulatorintended for medical purposes thatrepeatedly contracts muscles bypassing electrical currents throughelectrodes contacting the affect bodyarea.	Same
Device Name	NeuroTriggerBasic(Device UnderReview)	Shenzhen XFT-2000(Predicate Device)	Comparison
Indications for Use	NeuroTrigger Basic is indicated forthe prevention or retardation ofdisuse atrophy and muscle re-education to maintain or increaserange of motion.	XFT-2000 is intended for thefollowing use:- Relaxation of muscle spasms- Prevention or retardation ofdisuse atrophy- Increasing local blood circulation- Muscle re-education- Immediate post-surgical stimulationof calf muscles to prevent venousthrombosis- Maintaining or increasing rangeof motion- Adjunctive treatment in themanagement of post-surgicaland post-traumatic acute pain.	Substantially equivalent
Technology	Electrical Muscle Stimulation (EMS)	Electrical Muscle Stimulation(EMS)	Same
Power Source- method of line current isolation	N/A (battery operated)	N/A (battery operated)	Same
Battery	One rechargeable Lithium, Prismatic,4.2V (3.7 nominal), 120 milliamperehour (mAh)	3 AAA batteries	Substantially equivalent
- Number	- 1 battery in stimulator
- Size	- 31 x 12 mm, 4.95 mm thick
- Type	- LiPol 4.2 V Lithium ion battery
Device Name	NeuroTriggerBasic(Device UnderReview)	Shenzhen XFT-2000(Predicate Device)	Comparison
- Patient leakage current- Normal condition- Single fault condition	<1.4 μΑ<1.4 μΑ	N/AN/A	Although no data is available forthe predicate device, the leakagecurrent is similar or lower than thatof other cleared similar devices,so this does not introduce anynew safety concerns. In addition,the leakage current meets FDAguidance requirements.Note that this parameter is notapplicable to device effectiveness.
Average DC current throughelectrodes when device is on butno pulses are being applied	0 μΑ	0 μΑ	Same
Number of output modes	1 mode for neuromuscularstimulation (NMES)	1 mode for NMES1 mode for transcutaneouselectrical nervestimulation(TENS)	Substantially equivalent
Programs	- Unlimited number of programscan be created by the user- Frequency, pulse duration,amplitude, ramp up time, andtime on/offcan be adjusted	- 10 pre-set NMES programs- 3 pre-set TENS programs- User can create and savecustom programs- Frequency, pulse duration,amplitude, treatment time, andtime on/off can be adjusted	Substantially equivalent
Device Name	NeuroTriggerBasic(Device UnderReview)	Shenzhen XFT-2000(Predicate Device)	Comparison
Number of output channels	1 channel	2 channels	Substantially equivalent
- synchronous or alternating	N/A	- Both
- method of channel isolation		- Transistor
Regulated current or voltage	Constant current (also referred to as regulated current)	Regulated current	Same
Software / Firmware/MicroprocessorControl?	Yes, software and firmware	Yes	Same
Automatic overload trip?	Yes, if a zero load is connected, current shuts off	Yes	Same
Automatic no-load trip?	Yes, if no load is connected, current shuts off	Yes	Same
Automatic shut off	Yes	Yes	Same
User override control?	Yes	Yes, pause button	Same
Device Name	NeuroTriggerBasic(Device UnderReview)	Shenzhen XFT-2000(Predicate Device)	Comparison
Indicator Display:- On / Off Status	- Yes	- Yes	Same
- Low Battery?	- Yes	- Yes	Same
- Voltage / Current Level?	- Yes	- Yes	Same
Timer Range (min)(NMES mode)	Open Stimulation period	60 min	Different.The NTB IFU contains thefollowing Caution statement: "TheNeuroTrigger Basic device shouldbe used for a maximum durationof 120 minutes per session.Longer use of the device couldlead to skin irritation, burning, orother effects related tooverstimulation." Otherneuromuscular stimulationdevices within product code IPFthat are cleared for use bypatients at home have a similarmaximum duration of use,including the Shoulder Pacemaker(K220994).
Compliance with voluntarystandards?	IEC 60601-1IEC 60601-1-2IEC 60601-1-6IEC 60601-1-11IEC 60601-2-10ISO 10993-1 Part 1	IEC 60601-1IEC 60601-1-2IEC 60601-2-10	Same
Device Name	NeuroTriggerBasic(Device UnderReview)	Shenzhen XFT-2000(Predicate Device)	Comparison
Compliance with 21 CFR 898?	Yes	Yes	Same
Weight	11.9 g	96 g	Substantially equivalent
Dimensions (mm)	65 x 60 x 13	114 x 66 x 20	Substantially equivalent
Housing material	ABS, injection molding	Silicone & ABS	Substantially equivalent

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Device Name	NeuroTrigger Basic(Device Under Review)	Shenzhen XFT-2000(Predicate Device)	Comparison
Waveform and shape	Pulsed, symmetric, balance biphasic, rectangular, with interphase interval	Pulsed, symmetric, balancedBiphasic, Rectangular	Same
Area of electrode(s)	1.5 cm²	19.6 cm²	Different, but does not raise newquestions of safety oreffectiveness.
Dimensions of electrode(s)	1.4 cm diameter (round)	5 cm diameter (round)	See discussion below.
Maximum output voltage@ 500 Ω ± 10%	12.5 V	29.7 V	Different, but does not raise newquestions of safety oreffectiveness.
@ 2 kΩ ± 10 %	50 V	89.1 V	See discussion below.
@ 10 kΩ ± 10%	90 V (maximum voltage remains constant at a load larger than 3.6 kΩ)	125 V	Different, but does not raise newquestions of safety oreffectiveness.
Maximum output current@ 500 Ω ± 10 %	25 mA	59.4 mA	Different, but does not raise newquestions of safety oreffectiveness.
@ 2 kΩ ± 10%	25 mA	44.5 mA	See discussion below.
@ 10 kΩ ± 10%	9 mA	12.5 mA	See discussion below.
Device Name	NeuroTrigger Basic(Device Under Review)	Shenzhen XFT-2000(Predicate Device)	Comparison
Maximum Phase Charge			Substantially equivalent
@ 500 Ω	15.0 µC	10.8 µC	The calculation of the maximum
@ 2 kΩ	15.0 µC	15.6 µC	phase charge of the predicatedevice was based on themaximum phase duration and themaximum current amplitudedelivered into the correspondingload
@ 10KΩ	5.4 µC	4.4 µC
Pulse (phase) width	80 - 600 µs	100 - 350 µs	Different, but does not raise newquestions of safety or effectiveness.Although the maximum phaseduration of the subject device islonger that the predicate, thereare other stimulators using alonger phase duration. Forexample, Sonicator Plus(K071137) uses a max phaseduration of 500 µs.
Frequency (Hz)	10 - 300 Hz	100-350 Hz	Substantially equivalent
Net Charge (µCper pulse)(If zero, state method ofachieving zero net charge	ZeroBiphasic, charge balancedstimulation	ZeroBiphasic, charge balancedstimulation	Same
Device Name	NeuroTrigger Basic(Device Under Review)	Shenzhen XFT-2000(Predicate Device)	Comparison
Maximum Power Density, (W/cm²)(using smallest electrodeconductive surface area)	19.1 mW/cm² @ 500Ohm	8.9 mW/cm² @ 500Ohm	Different, but does not raise newquestions of safety oreffectiveness.Per FDA Guidance the maximumpower density should be less than25 mW/cm²
Max current (RMS) (mA)@ 500 Ω	7.57	16.9	Different, but does not raise newquestions of safety or effectiveness.The maximum RMS current is lowerin the subject device than thepredicate device. RMS value issimply a combination of currentamplitude, pulse width, pulsefrequency, and burst duty cycle.The RMS value by itself doesn'tdefine the physiological response,and the stimulation parameters areaddressed in the discussion below.Thus the difference in the RMSvalue does not raise neweffectiveness concerns.
Device Name	NeuroTrigger Basic(Device Under Review)	Shenzhen XFT-2000(Predicate Device)	Comparison
Burst Mode (i.e., pulse trains)a) Pulses per burstb) Bursts per secondc) Burst duration (seconds)d) Duty Cycle[Line (b) x Line (c)]	a) 10 - 300 pulsesb) 0.09 - 0.32 Hzc) 0.1 - 1.0 sd) Duty cycle:0.9% - 32%	a) 1 - 625 pulsesb) 0.05 - 0.5 Hzc) 1 - 5 sd) Not available	Different, but does not raise newquestions of safety oreffectiveness.There is some overlap betweenthe ranges of the subject andthe predicate device. Also, theNTB burst mode parameters areeffectively a derivative of thetime on and time off parameterslisted in the next two lines of thistable.• Burst duration is ON Time.• Pulses per burst arecalculated as ON Timemultiplied by the pulsefrequency.• Burst per seconds iscalculated as an inverse ofON Time + OFF time.Both ON Time and OFF Timeranges comply with the FDAGuidance for Powered MuscleStimulators.
Device Name	NeuroTrigger Basic(Device Under Review)	Shenzhen XFT-2000(Predicate Device)	Comparison
Connectivity	Bluetooth Low Energy (BLE 5.2)connectivity to Android platform-based app	N/A	Different, but does not raise newquestions of safety oreffectiveness.Many neurostimulators use BLEconnectivity to communicatebetween the stimulator and acustom app (e.g. VitalStimK153224 and PowerDotK210938), so this feature doesnot raise new questions of safetyor effectiveness.

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Discussion of Differences in Stimulation Output Specifications

In terms of individual stimulation parameters, the area of the NTB electrodes, the maximum output voltage, maximum output current, and duty cycle are lower than the predicate device, while the maximum frequency is higher with the NTB device. The impact of these stimulation output specifications on comparability of the NTB to the XFT-2000 device and on the safety and effectiveness of the NTB device are discussed below.

. Safety
- Each of the stimulation output specifications of the subject device that differs from O the predicate device (with the exception of the phase width) is lower than that of the predicate, thus they do not present safety concerns.
- The maximum phase width of the subject device is higher than the predicate. O Safety-wise, longer phase duration increases current density and the power density, however the resulting values are still within the safety limits.
. Effectiveness

While differences in individual output specifications have been noted in Table 14-2 above, to assess the impact of the output specifications on the intended use of the device and how the NTB device compares to the predicate device, one must consider them in combination as it is the combination of these parameters, not the individual parameters themselves, that determines the physiological response to stimulation. It is well-established in neurostimulation that it is possible to achieve the same response of the muscle or nerve using different stimulation parameters. One can adjust the pulse duration, pulse amplitude, pulse frequency and spacing of electrodes to achieve similar muscle contractions with different stimulation parameters.

An example of the interplay between different stimulation parameters is the strengthduration curve, which is commonly used in electrophysiology. The strength-duration curve shows that the same stimulation effect can be achieved by adjusting either the pulse duration or the pulse amplitude, as long as the delivered electrical charge remains the same. Thus stimulation intensity and the pulse duration should be considered together (as the resulting electrical charge) rather than being analyzed separately.

The NTB device is capable of delivering similar, and even slightly higher electrical charge as compared to the predicate XFT-2000, therefore the effectiveness of the NTB device is similar to the predicate.

Specific differences in individual output specifications between the NTB and the predicate XFT-2000 device are discussed below:

Maximum voltage at different loads: Since both the subject and the predicate O devices are current controlled, the maximum voltage developed by the device does not define the delivered current, and thus the voltage by itself does not impact the effectiveness of the device.
Maximum current delivered to the different loads is lower in the NTB than in the O predicate device. As mentioned above, the physiological response is dependent on the delivered charge rather than on the maximum value of the current. Thus the maximum value of the delivered current on its own does not affect the effectiveness of the device.
O The surface area of the subject electrodes is smaller than the predicate electrodes. It is known that smaller surface area electrodes require lower stimulation current to

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achieve the same physiological effect. For example, Alon et. al. and Li et. al. demonstrated a linear relationship between the electrode size and the amplitude of the current required to cause the physiological effect. 1-2 In addition, smaller electrodes require smaller spacing between them (i.e. the spacing between the stimulating and the return electrode), thus causing a larger gradient of the electrical potential in the tissue. Since the electrical potential is causing the depolarization and the activation of the nerve or muscle cell, smaller electrodes' spacing is an additional factor which allows the subject device to elicit the same physiological response with lower stimulation current.

Duty Cycle defines the ratio between the time duration when the stimulation is o applied (muscle contraction) and the time when the stimulation is not applied (muscle relaxation). The full cycle consists of muscle contraction followed by muscle relaxation. The predicate device delivers the cycle duration (stimulation ON time + stimulation OFF time) between 2 sec and 20 sec, while the subject device delivers cycles of 3 sec to 11 sec. Both ranges are sufficient for muscle contraction and subsequent muscle relaxation, not raising new concerns of safety or effectiveness.
In summary, the differences in stimulation output parameters do not introduce any new safety concerns as the output parameters are, in general, lower than the predicate device. Despite the fact that certain stimulation parameters of the NTB are lower than the predicate device, the NTB can still effectively activate muscles because the ability to activate muscles is more dependent on the combination of stimulation parameters and electrode placement rather than individual stimulation parameters. Thus, it can be concluded that the set of the stimulation parameters of the subject device is substantially equivalent to that of the predicate device.

Discussion on the non-clinical testing performed

Performance testing was performed to assure safety and effectiveness of the NeuroTrigger Basic device. All necessary bench testing was conducted on the NeuroTrigger Basic device to ensure conformance to design specifications and to support a determination of substantial equivalence to the predicate device. [807.92(b)(1)] The nonclinical, bench testing performed included:

-Biocompatibility testing: The NTB device components that come in direct contact with patient intact skin were tested. Cytotoxicity, sensitization, and irritation testing were performed to establish that the device is safe and effective for human use on intact skin.
- Cytotoxicity: the NTB device was tested according to ISO 10993-5, and O passed successfully demonstrating that it is non-cytotoxic
- Sensitization: NTB device tested according to ISO 10993-10 and passed. The O device does not cause skin sensitization
- Irritation: NTB device tested according to ISO 10993-23 and passed. The O Device is nonirritant.
Packaging, shelf life, and transit simulation testing were tested on the NTB device, which included the following tests:
- Shipment simulation test: the NTB device underwent simulation O testing following the ASTM D4332-14 and ASTM D4169-16 standards.
- o Accelerated Aging 1 yr: After passing the shipment simulation test, the device

1 Alon G., Kantor G., Ho. H. Effects of electrode size on basic excitatory responses and on skeletal stimulus parameters. Journal of Orthopaedic & Sports Physical Therapy. Volume 20 Number 1 July 1994.

2 Li P., Chai G., Zhu K., Lan N., Sui X. Effects of electrode size and spacing on sensory modalities in the phantom thumb perception area for the forearm amputees. Annu Int Conf IEEE Eng Med Biol Soc, 2015:3383-6.

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underwent accelerated aging for 1 year following the ASTM F1980-16 standard.

Device performance: NTB was tested after passing the 1 yr accelerated aging o period and performed according to device requirements. Device is safe and effective for patient use after 1 year aging.
-Performance testing, NTB device was tested prior and post environmental and aging testing to ensure that the device performs according to its design specifications and is safe and effective for use post shelving for at least 1 year. The performance testing can be divided into the following categories:
- Mechanical (including device assembly) O
- Electrical o
- Functional; and O
- Usability O
-Software verification and validation testing was conducted to test for the safe and secure use of the software with the NTB device, which included Bluetooth connection, stimulation parameter identification, and cybersecurity protection. Device function performs as expected and according to software requirements.
-Electrical safety and EMC testing. The NTB device was tested according to the EN60601-1 & IEC60601-1-2 standards for EMC and electrical safety and passed. Furthermore, the device complies with FCC regulation 47CRF15, Section 15.247. The device is safe for patient use.

CONCLUSION:

The NeuroTrigger Basic device is substantially equivalent to the predicate device Shenzhen XFT-2000 (K193275). Both the subject device and the predicate device use electrodes to deliver stimulation to patients' muscles.

The stimulation parameters of NTB are similar to the predicate device. The comparison of the device under review, and the predicate device can be seen in the tables above (Table 1 and Table 2). The NTB device is designed to comply with relevant safety recognized consensus standards. Detailed and strictly controlled testing has been carried out.

Furthermore, tests results and risk analysis show that the NeuroTrigger Basic is a safe for the intended use, and differences between the NTB and the predicate device do not raise any new questions of safety or effectiveness.

These data support that the NeuroTrigger Basic device is substantially equivalent to the predicate device.

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).