K Number
K140467
Device Name
FLEX-MT +
Manufacturer
Date Cleared
2014-10-07

(225 days)

Product Code
Regulation Number
890.5850
Reference & Predicate Devices
Predicate For
N/A
AI/MLSaMDIVD (In Vitro Diagnostic)TherapeuticDiagnosticis PCCP AuthorizedThirdpartyExpeditedreview
Intended Use

As prescribed by a physician for the following:

TENS- Transcutaneous Nerve Stimulation

  • Symptomatic relief of chronic intractable pain .
  • . Post traumatic and post surgical pain relief

EMS- Electrical Muscle Stimulation

  • . Relaxation of muscle spasm
  • . Increasing local blood circulation
  • . Muscle re-education
  • . Prevention or retardation of disuse atrophy
  • Prevention of venous thrombosis of the calf muscles immediately after surgery
  • . Maintaining or increase range of motion
Device Description

The Flex-MT + is a combination TENS and EMS device which delivers nerve or muscle stimulation by applying an electrical current to electrodes, which are attached on the patient's skin. The output and waveform is adjustable according to the intended treatment of patient. The stimulator has 2 output channels, accessed through jacks at the top of the housing, so that it may stimulate either 2 or 4 patient electrodes. The device is powered by 700 mAh 4.8V Ni MH rechargeable battery pack. A patient compliance timer can memorize 60 sets of operation records; the total recordable time is 999 hours.

AI/ML Overview

The provided text is a 510(k) summary for the Flex-MT+ device. It outlines the device's technical specifications and compares them to predicate devices to establish substantial equivalence.

Here's an analysis of the acceptance criteria and the "study" (in this case, performance testing) that proves the device meets them, based on the provided text:

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

The document does not explicitly state "acceptance criteria" for performance, but rather demonstrates substantial equivalence by comparing the Flex-MT+ device's technical characteristics and performance to two predicate devices (K083030 EMSI TENS-EMS-14 (Flex MT) and K021100 EMPI 300 PV). The "Comment" column in the provided tables effectively acts as the "acceptance criteria" by stating whether the subject device's performance is comparable to or within acceptable limits of the predicate devices and relevant standards.

Acceptance Criteria (Derived) and Reported Device Performance (Flex-MT+)

CharacteristicAcceptance Criteria (Derived from Predicates & Standards)Reported Device Performance (Flex-MT+)Fulfilled?
Indications for UseSame as predicate TENS and NMES modes.Same as K083030 EMSI TENS-EMS-14 (Flex MT) and K021100 EMPI 300 PVYes
Power SourceBattery operated; battery charger available (consistent with EMPI predicate).700 mAh 4.8V Ni-MH, rechargeable battery pack and chargerYes
Patient Leakage Current< 1 microamp (consistent with EMSI predicate).< 1 microampYes
Number of Output Modes2 (consistent with EMSI predicate).2Yes
Number of Output Channels2 (consistent with both predicates).2Yes
Method of Channel IsolationTransformer (consistent with both predicates).TransformerYes
Regulated Current or Voltage?Regulated Voltage (consistent with EMSI predicate).Regulated VoltageYes
Software/Firmware/MicroprocessorYes (consistent with both predicates).YesYes
Automatic Overload Trip?Provides additional safety (improved over EMSI predicate).YesYes
Automatic Shut Off?Yes (consistent with both predicates).YesYes
Patient Override Control?Yes (consistent with both predicates).YesYes
Indicator Display (On/Off, Low Bat, Voltage/Current)Yes (consistent with both predicates).Yes (1-10 bars displayed for Voltage/Current Level)Yes
Timer Range (minutes)Minor difference from EMPI predicate is acceptable and does not affect safety/effectiveness.5-90 minutes, or continuousYes
Compliance with Voluntary StandardsANSI/AAMI ES1-1993, IEC 60601-1-2 as applicable (consistent with EMSI predicate).ANSI/AAMI ES1-1993, IEC 60601-1-2 as applicableYes
Compliance with 21 CFR 898?Yes (consistent with both predicates).YesYes
Weight & DimensionsMinor differences do not change device performance.156 g (with battery), 12cm x 5.4cm x 3.3cmYes
Housing MaterialsPlastic (consistent with both predicates).PlasticYes
Waveform (TENS/EMS)Asymmetrical biphasic / Biphasic symmetrical (consistent with both predicates).Asymmetrical biphasic / Biphasic symmetricalYes
Waveform ShapeRectangular (consistent with both predicates).RectangularYes
Maximum Output VoltageWithin the range of predicates and acceptable limits of IEC 60601-1.43.2V @ 500ΩYes
Maximum Output CurrentWithin the range of predicates and acceptable limits of IEC 60601-1.86.4mA @ 500ΩYes
Pulse Width per phaseSame or increased selection as predicates.50-400µsec (consistent with EMPI predicate)Yes
Pulse FrequencySame available frequencies as predicates.2-150 HzYes
Net Charge ($\mu$C per pulse)Within acceptable limits of IEC 60601-1.14.6 @ 500Ω (TENS), 0 (EMS)Yes
Maximum Current Density (mA/cm²)Within acceptable limits of IEC 60601-1.1.83 @500Ω (TENS), 2.82 @500Ω (EMS)Yes
Maximum Power Density (W/cm²)Within acceptable limits to avoid thermal burn.0.000858W/cm2 @500ΩYes
Additional FeaturesPatient compliance timer, battery charger (consistent with predicates).Patient compliance timer, battery chargerYes

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

The document explicitly states: "No clinical study data is provided in support of this submission."
Therefore, there is no "test set" in the sense of clinical data from patients. The evaluation is based on technical, electrical, and mechanical performance testing, likely conducted on a single or a few units of the device to verify its specifications. The document doesn't specify the sample size for these technical performance tests. The data provenance would be laboratory testing by the manufacturer (EMSI).

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

Not applicable. Since no clinical study or test set involving human interpretation of medical data was conducted, no experts were used to establish ground truth in that context. The "ground truth" for the technical performance is derived from recognized industry standards (IEC, ANSI/AAMI) and the specifications of the predicate devices.

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

Not applicable, as there was no test set requiring human 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 a powered muscle stimulator/transcutaneous nerve stimulator, not an AI-powered diagnostic or assistive tool for human readers. No MRMC study was performed.

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

Not applicable. This device is a stimulator, not an algorithm, and its performance is assessed based on its physical and electrical outputs, not an algorithmic standalone performance.

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

The "ground truth" for evaluating the Flex-MT+ device's technical characteristics and performance is based on:

  • Industry Standards: IEC 60601-1, IEC 60601-1-2, IEC 60601-2-10, IEC 60601-1-11, EN 60601-1-4, EN 62304, and ANSI/AAMI ES1-1993. The device's compliance with these standards serves as a form of "ground truth" for safety and basic performance.
  • Predicate Device Specifications: The technical specifications (e.g., maximum output voltage, current, pulse width, frequency) of the legally marketed predicate devices (K083030 EMSI TENS-EMS-14 (Flex MT) and K021100 EMPI 300 PV) serve as the benchmark for substantial equivalence. The argument is that if the new device's specifications are within acceptable ranges of previously cleared devices, it is substantially equivalent.

8. The sample size for the training set

Not applicable. This device is not an AI/machine learning model, so there is no training set.

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

Not applicable. As there is no training set for an AI/ML model, there is no ground truth established for a training set.

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Image /page/0/Picture/1 description: The image is a black and white logo for the U.S. Department of Health & Human Services. The logo features a stylized image of three human profiles facing right, stacked slightly offset from each other. The profiles are connected by a flowing line that forms the base of the design. The text "DEPARTMENT OF HEALTH & HUMAN SERVICES - USA" is arranged in a circular pattern around the image.

Food and Drug Administration 10903 New Hampshire Avenue Document Control Center - WO66-G609 Silver Spring, MD 20993-0002

October 7, 2014

EMSI % Cherita James M Squared Associates, Inc. 815 King St. Suite 206 Alexandria, VA 22314

Re: K140467

Trade/Device Name: Flex-MT+ Regulation Number: 21 CFR 890.5850 Regulation Name: Powered muscle stimulator Regulatory Class: Class II Product Code: IPF, GZJ Dated: August 20, 2014 Received: August 22, 2014

Dear Ms. James:

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. 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.

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

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CFR Part 807); labeling (21 CFR Part 801); medical device reporting (reporting of medical device-related adverse events) (21 CFR 803); good manufacturing practice requirements as set forth in the quality systems (OS) regulation (21 CFR Part 820); and if applicable, the electronic product radiation control provisions (Sections 531-542 of the Act); 21 CFR 1000-1050.

If you desire specific advice for your device on our labeling regulation (21 CFR Part 801), please contact the Division of Industry and Consumer Education at its toll-free number (800) 638-2041 or (301) 796-7100 or at its Internet address

http://www.fda.gov/MedicalDevices/ResourcesforYou/Industry/default.htm. Also, please note the regulation entitled, "Misbranding by reference to premarket notification" (21CFR Part 807.97). For questions regarding the reporting of adverse events under the MDR regulation (21 CFR Part 803), please go to

http://www.fda.gov/MedicalDevices/Safety/ReportaProblem/default.htm for the CDRH's Office of Surveillance and Biometrics/Division of Postmarket Surveillance.

You may obtain other general information on your responsibilities under the Act from the Division of Industry and Consumer Education at its toll-free number (800) 638-2041 or (301) 796-7100 or at its Internet address

http://www.fda.gov/MedicalDevices/ResourcesforYou/Industry/default.htm.

Sincerely yours,

Felipe Aquel -S

  • Carlos L. Peña, Ph.D., M.S. for Director Division of Neurological and Physical Medicine Devices Office of Device Evaluation Center for Devices and Radiological Health
    Enclosure

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Indications for Use

510(k) Number (if known) K140467

Device Name Flex-MT +

Indications for Use (Describe)

TENS - Transcutaneous Nerve Stimulation

  • · Symptomatic relief of chronic intractable pain
    · Post traumatic and post surgical pain relief

EMS - Electrical Muscle Stimulation

  • · Relaxation of muscle spasm
  • Increasing local blood circulation
  • · Muscle re-education
  • · Prevention or retardation of disuse atrophy
  • · Prevention of venous thrombosis of the calf muscles immediately after surgery
  • · Maintaining or increase range of motion

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

Registration Use (Part 21 CFR 201.Subpart D) Over-The-Counter Use (21 CFR 201.Subpart C)
-----------------------------------------------------------------------------------------------------------------------------------------------------

Prescription Use (Part 21 CFR 801 Subpart D)

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

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510(K) SUMMARY

The following information is provided as required by 21 CFR § 807.92 for EMSI's Flex-MT + 510(k) premarket notification. In response to the Safe Medical Devices Act of 1990, the following is a summary of the information upon which the substantial equivalence determination is based.

  • Sponsor: EMSI 3504 Cragmont Dr. Suite#100 Tampa, Florida 33619 Ph: 813-471-0129 Fax: 813-471-0130 Registration Number: 3003573572
    M Squared Associates, Inc. Contact: Cherita James 815 King Street, Suite 206 Alexandria, VA 22314 Ph. 703-562-9800 Ext 257 Fax. 703-562-9797
Date of Submission:September 30, 2014
Proprietary Name:Flex-MT +
Common Name:Powered Muscle Stimulator, Transcutaneous Nerve Stimulator
Regulatory Class:II
Regulation:21 CFR 890.5850, 21 CFR 882.5890
Panel:Physical Medicine
Product Codes:IPF, GZJ
Predicate Device(s):K083030 EMSI TENS-EMS-14 (Flex MT), K021100 EMPI 300 PV

The Flex-MT + is a combination TENS and EMS device which delivers Device Description: nerve or muscle stimulation by applying an electrical current to electrodes, which are attached on the patient's skin. The output and waveform is adjustable according to the intended treatment of patient. The stimulator has 2 output channels, accessed through jacks at the top of the housing, so that it may stimulate either 2 or 4 patient electrodes. The device is powered by 700 mAh 4.8V Ni

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MH rechargeable battery pack. A patient compliance timer can memorize 60 sets of operation records; the total recordable time is 999 hours.

Intended Use: As prescribed by a physician for the following:

TENS- Transcutaneous Nerve Stimulation

  • Symptomatic relief of chronic intractable pain .
  • . Post traumatic and post surgical pain relief

EMS- Electrical Muscle Stimulation

  • . Relaxation of muscle spasm
  • . Increasing local blood circulation
  • . Muscle re-education
  • . Prevention or retardation of disuse atrophy
  • Prevention of venous thrombosis of the calf muscles immediately after surgery
  • . Maintaining or increase range of motion

Performance Testing

The Flex-MT + is compliant with the following standards and has outputs which are within the same range as the predicate devices.

  • . IEC 60601-1:2005 = Corr 1:2006, Corr 2:2007 Medical Electrical Equipment - Part 1: General Requirements For Safety
  • . IEC 60601-1-2:2007/AC:2010 Medical Electrical Equipment - Part 1-2: General Requirements For Safety - Collateral Standard: Electromagnetic Compatibility -Requirements And Test
  • IEC 60601-2-10 Edition 2.0 2012-06 Medical electrical equipment -- Part 2-10: Particular requirements for the basic safety and essential performance of nerve and muscle stimulators
  • IEC 60601-1-11:2010 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.
  • EN 60601-1-4:1996+A1:1999 Medical device Programmable Electrical Medical Systems (PEMS);
  • . EN 62304 : 2006/AC:2008 Medical device software-Software life cycle processes.

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Technical and Performance Comparison

Both the subject device and the predicate device are battery powered, handheld devices with similar unit characteristics including device controls, power supply, output modes and channels, waveforms, output voltage, current and pulse durations, as well as device material.

Subject DeviceFlex-MT +Predicate K08303EMSI TENS-EMS-14(Flex MT)PredicateK021100EMPI 300PV(TENS/NMESmodes)Comment
Indication for UseTENS-TranscutaneousNerve Stimulation•Symptomaticrelief of chronicintractable pain•Post traumaticand post surgicalpain reliefEMS- ElectricalMuscleStimulation•Relaxation ofmuscle spasm•Increasing localblood circulation•Muscle re-education•Prevention orretardation ofdisuse atrophy•Prevention ofvenousthrombosis of thecalf musclesimmediately aftersurgery•Maintaining orincrease range ofmotionTENS-TranscutaneousNerve Stimulation•Symptomaticrelief of chronicintractable pain•Post traumatic andpost surgical painreliefEMS- ElectricalMuscle Stimulation•Relaxation ofmuscle spasm•Increasing localblood circulation•Muscle re-education•Prevention orretardation ofdisuse atrophy•Prevention ofvenous thrombosisof the calf musclesimmediately aftersurgery•Maintaining orincrease range ofmotionTENS-TranscutaneousNerve Stimulation•Symptomaticrelief of chronicintractable pain•Adjunctivetreatment for postsurgical and posttrauma painEMS- ElectricalMuscle Stimulation•Relaxation ofmuscle spasm•Increasing localblood circulation• Re-educationmuscles• Retarding orpreventing disuseatrophy•Prevention ofvenous thrombosisof the calf musclesimmediately aftersurgery•Maintaining orincrease range ofmotionSame indicationsin the subject andpredicates TENSand NMES modes.
Subject DeviceFlex-MT +Predicate K08303EMSI TENS-EMS-14(FlexMT)PredicateK021100EMPI 300PVComment
4. Power Source700 mAh 4.8VNi-MH,rechargeablefour batteries, sizeAA, alkalineTwo batteries, sizeAA rechargeable,and chargerAll devices arebattery operated.The subject and
Subject DeviceFlex-MT +Predicate K08303EMSI TENS-EMS-14(FlexMT)PredicateK021100EMPI 300PVComment
battery pack andchargerEMPI devicesoffer a batterycharger.
– Methodof Line CurrentIsolationn/an/an/aNA
- PatientLeakage Current- Normal condition- Singlefault conditionnot measurable< 1 microampnot measurable< 1 microampUnknownThe subject andEMSI predicatehave the samePatient Leakagelevel
5. Number ofOutput Modes224The subject andEMSI predicatehave the samenumber ofchannels. TheEMPI predicatesoffers the same 2channels, as wellas 2 additionalchannels for theirIFS and FESoutputs.
6. Number ofOutput Channels222Same number andtype of outputchannels andchannel isolation.
- Synchronousor AlternatingSynchronous orAlternatingSynchronous orAlternatingSynchronous orAlternating
– Method ofChannel IsolationTransformerTransformerTransformer
7. RegulatedCurrent orRegulated Voltage?RegulatedVoltageRegulated voltageUnknownSame regulatedvoltage method asthe EMSI predicatedevice.
8.Software/Firmware/MicroprocessorControl?YesYesYesAll devices aresoftware controlled
9. AutomaticOverload Trip?YesNoUnknownThe automaticoverloadprotectionprovides additionalsafety whenoperating thesubject device
Subject DeviceFlex-MT +Predicate K08303EMSI TENS-EMS-14(FlexMT)PredicateK021100EMPI 300PVComment
11. Automatic ShutOff?YesYesYesSame features
12. PatientOverride Control?YesYesYesSame features
13. IndicatorDisplay:On/Off Status?Low Battery?Voltage/CurrentLevel?YesYesYes (1-10 barsdisplayed)YesYesYes (1-10 barsdisplayed)YesYesYesSame features
4. Timer Range(minutes)5-90 minutes, orcontinuous5-90 minutes, orcontinuous5-99 minutes, orcontinuousMinor timerdifference whencompared to theEMPI predicate donot affect safety oreffectiveness.
15. Compliancewith VoluntaryStandards?ANSI/AAMIES1-1993IEC 60601-1-2 asapplicableANSI/AAMI ES1-1993IEC 60601-1-2 asapplicableUnknownNA
16. Compliancewith 21 CFR 898?YesYesYesSame features
17. Weight156 g (includingbattery)140 g226gMinor differencesin weight and
18. Dimensions [Wx H x D]12cm x 5.4cm x3.3cm12 cm x 5.5cm x2.5cmunknowndimensions do notchange device
19. HousingMaterials andConstructionplasticplasticplasticperformance.Same materials.

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Subject Device- Flex-MT +Predicate K083030EMSI TENS-EMS-14(Flex MT)Comments
TENS modeEMS modeTENS modeEMS mode
WaveformAsymmetricalbiphasicBiphasicsymmetricalAsymmetricalbiphasicBiphasicsymmetricalAsymmetricalbiphasicBiphasicsymmetricalAsymmetricalbiphasicBiphasicsymmetricalSamewaveforms
ShapeRectangularRectangularRectangularRectangularSameshape
MaximumOutputVoltage43.2V @ 500Ω43.2V @ 500Ω41V@500 Ω28V@500 Ω41V @ 500 Ω29.5V@ 500 ΩThemaximumoutputvoltage @500Ω ofthe subjectdevice iswithin therange ofthe EMSIand EMPIpredicates.All withinacceptablelimits ofIEC60601-1
MaximumOutputCurrent82mA @ 500Ω56mA @ 500Ω82 mA @500Ω59 mA@500ΩSubjectdevice hasincreaseoutputcurrentavailablewhencomparedto theEMSIpredicate,but withinrange ofthe EMPIpredicate.All withinacceptablelimits ofIEC60601-1
86.4mA @ 500Ω86.4mA @500Ω86.4mA @ 500Ω86.4mA @ 500Ω
PulseWidth perphase50-400µsec50-400µsec50-300 µsec50-300 µsecSubjectdevice hasincreasedselectionof pulsewidthoptionwhencomparedto EMSIpredicate,but sameoption asEMPIpredicate.
MaxPhaseDuration(PositivePhase)$400\mu s$=0.4ms$400\mu s$=0.4ms$400\mu s$=0.4ms$400\mu s$=0.4msN/A50-300 $\mu s$N/A50-300 $\mu s$
MaxPhaseDuration(NegativePhase)2.6ms$400\mu s$=0.4ms2.6ms$400\mu s$=0.4ms--
PulseFrequencyMax Dutyfactor2-150 Hz0.0602-150 Hz0.1202-150 Hz0.0602-150 Hz0.1202-150Hz0.0452-150 Hz0.0902-150Hz0.0452-150 Hz0.090Samepulsefrequencies available
Subject Device- Flex-MT +Predicate K083030EMSI TENS-EMS-14(Flex MT)
Multi-phasicwaveformsYesyesYesyesyesyesyesyes
NetCharge( $\mu$ C perpulse)14.6 @ 500 $\Omega$0(symmetricalphases resultin 0)14.6 @ 500 $\Omega$0(symmetricalphases)24.5 @ 500 $\Omega$0 (symmetricalphases)24.6 $\mu$ C @500 $\Omega$0(symmetrical phases)All withinacceptablelimits ofIEC 60601-1

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MaximumCurrentDensity,(mA/cm²)1.83 @500Ω2.82 @500Ω1.83 @500Ω2.82 @500Ω0.26 @500 Ω0.35 @ 500 Ω0.26 @ 500 Ω0.37 @ 500 ΩAll withinacceptablelimits ofIEC60601-1
MaximumPowerDensity,(W/cm²)0.000858@500Ω0.000858@500Ω0.000858@500Ω0.000858@500 Ω0.0105@ 500 Ω0.0098 @ 500 Ω0.0105 @500 Ω0.0109 @500 Ω
MaximumPulseDuration400µs+2.6ms=0.4ms+2.6ms=3.0ms400µs+400µs=800µs=0.8ms400µs+2.6ms=0.4ms+2.6ms=3.0ms400µs+400µs=800µs=0.8ms----
AdditionalFeatures(ifapplicable)Patient compliance timer, battery chargerPatient compliance timer

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Subject Device- Flex-MT +Predicate K021100EMPI 300 PV (TENS and EMSmodes only)Comments
TENS modeEMS modeTENS and EMS modeSame modes
WaveformAsymmetricalbiphasicBiphasicsymmetricalAsymmetricalBiphasicbiphasicsymmetricalAsymmetrical biphasic, BiphasicsymmetricalSame waveforms
ShapeRectangularRectangularRectangularSame shape
MaximumOutputVoltage43.2V @ 500Ω43.2V @ 500Ω43.2V @ 500Ω43.2V @ 500Ω50V@500 ΏThe maximum output voltage of thesubject device is within the range ofthe EMSI and EMPI predicates. Allwithin acceptable limits of IEC60601-1
MaximumOutputCurrent86.4mA @ 500Ω86.4mA @500Ω86.4mA @ 500Ω86.4mA @500Ω100mA @, 500 ΏThe maximum output current of thesubject device is within the range ofthe EMSI and EMPI predicates. Allwithin acceptable limits of IEC60601-1
PulseWidth perphase50-400 usec50-400 usec50-400 usecSame range
Max PhaseDuration(PositivePhase)400us=0.4ms400us=0.4ms400us=0.4ms400us=0.4ms
Max PhaseDuration(NegativePhase)2.6ms400us=0.4ms2.6ms400us=0.4ms
Phaseduration50-400 µsec50-400 µsec50-400 µsec50-400 µsecUnknown---
NetCharge(µC perpulse)14.6 @500Ω0(symmetricalphases resultin 0)14.6 @500Ω0(symmetricalphases)Unknown---
MaximumPhaseCharge,( μ C)14.6uC@ 500Ω0uC @ 500Ω14.6 uC @500Ω0 uC @500Ω40 uC @ 500 ΏAll within acceptable limits of IEC60601-1
MaximumCurrentDensity,(mA/cm²)14.6 @500Ω0@500Ω14.6 @500Ω0@500Ω0.84 @ 500 Ω2"square electrodeAll within acceptable limits of IEC60601-1
MaximumPowerDensity,(W/cm²)0.000858W/cm2@500Ω0.000858W/cm2@ 500Ω0.000858W/cm2@500Ω0.000858W/cm2@500Ω0.0088W/cm2 @ 500 Ώ2"square electrodeAll within acceptable limits to avoidthermal burn.
MaximumPulseDuration400µs+2.6ms=0.4ms+2.6ms=3.0ms400µs+400µs=800µs=0.8ms400µs+2.6ms=0.4ms+2.6ms=3.0ms400µs+400µs=800µs=0.8ms---
AdditionalFeatures(ifapplicable)Patient compliance timer, battery chargerBattery chargerSame feature

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Clinical Data: No clinical study data is provided in support of this submission.

Substantial Equivalence

Based on the Flex-MT+ and the predicate device technical characteristics, performance, and indications for use, the substantially equivalent to the EMSI Flex MT and the EMPI 300V. As detailed in the tables above, the differences between the subject and predicate devices do not adversely impact the FlexMT+ safety and effectiveness for it's substantial equivalence to the predicates.

§ 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).