Cleared Special

K251856 - Li-Battery Powered OTC TENS/EMS Combination Stimulator, Model Z4

K251856 is an FDA 510(k) clearance for Li-Battery Powered OTC TENS/EMS Combina..., manufactured by Everyway Medical Instruments Co.,Ltd. The device is a Class 2 Neurology device with product code NUH cleared through the Special 510(k) pathway after a 157-day FDA review.

K251856 · Everyway Medical Instruments Co.,Ltd · Neurology device
Download Printable Device Report (PDF) Official FDA 510(k) Summary (PDF)
Optimized for regulatory review, auditing and printing
Nov 2025
Decision
157d
Days
Class 2
Risk

K251856 is an FDA 510(k) clearance for the Li-Battery Powered OTC TENS/EMS Combination Stimulator, Model Z4. Classified as Stimulator, Nerve, Transcutaneous, Over-the-counter (product code NUH), Class II - Special Controls.

Submitted by Everyway Medical Instruments Co.,Ltd (New Taipei City, TW). The FDA issued a Cleared decision on November 21, 2025 after a review of 157 days - an extended review cycle.

This device falls under the Neurology FDA review panel, regulated under 21 CFR 882.5890 - the FDA neurology device framework. As a Special 510(k), this submission covers a manufacturer modification to an existing cleared device rather than a new device introduction.

Device pattern: Iterative device modification. Standard predicate reliance. This Special 510(k) clearance confirms that the manufacturer's modifications remained within the established regulatory envelope of the original cleared device.

FDA 510(k) Submission Details - K251856

510(k) Number K251856 FDA.gov
FDA Decision Cleared Substantially Equivalent - Traditional 510(k) (SESE)
Date Received June 17, 2025
Decision Date November 21, 2025
Days to Decision 157 days
Submission Type Special
Review Panel Neurology (NE)
Summary Summary PDF
Third-party Review No - reviewed directly by FDA
Combination Product No
PCCP Authorized No
Regulatory Context
Review time vs. panel average
8d slower than avg
Panel avg: 149d · This submission: 157d
Pathway characteristics
Modification to existing cleared device.

NUH Device Classification - Class 2, Special Controls

Product Code NUH Stimulator, Nerve, Transcutaneous, Over-the-counter
Device Class Class 2 - Special Controls
CFR Regulation 21 CFR 882.5890
Definition Temporary Relief Of Pain Due To Sore/aching Muscles
What this classification means

Class II devices require demonstration of substantial equivalence to a legally marketed predicate device. This pathway does not require clinical trials - it relies on engineering equivalence and performance data. Most Neurology devices follow this clearance model.

Regulatory Peers - NUH Stimulator, Nerve, Transcutaneous, Over-the-counter

All 230
Devices cleared under the same product code (NUH) and FDA review panel - the closest regulatory comparables to K251856.
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K251856 · Li-Battery Powered OTC TENS/EMS Combination Stimulator, Model Z4
Download PDF FDA Summary Everyway Medical Inst…