WHY THIS UNIT BORDERS ON MEDICAL FRAUD, and why it may be banned by the FDA if they found out about it (until they change their claims). This is all based on the Amazon description, which came from the manufacturer.
1) It claims to be both TENS and EMS, yet there is no setting to choose between the two. Using the two terms interchangeably is a common mistake, and a sure sign of fraud. TENS uses high frequency and low amperage, while EMS uses low frequency and higher amperage because they do different things. TENS target the nerves and you should feel a buzz, but the muscles shouldn't move. EMS targets the mucles so the muscles should move. TENS DOES NOT FEEL LIKE A MUSCULAR MASSAGE, I.E. KNEADING, BEATING, RUBBING.
2) It claims to be "Ideal for relieving sore muscles caused by exercise, muscle spasms, and carpal-tunnel syndrome." You don't relieve the pain of muscle spasms by causing more muscle spasms! Secondly, carpal-tunnel syndrome causes numbness, and rarely pain, in the fingers. It is caused by compression of nerves. None of the settings have anything to do with the fingers (no, the hand-foot button is something entirely different). No amount of electricity will uncompress the nerves, nor can you alleviate numbness. In fact, electrical stimulation can cause numbness.
3) It claims "This FDA-approved device has been prescriped by doctors, chiropractors, and physical therapists." It is only FDA-approved in the sense that such devices are considered safe. My bet is that this specific devices was never submitted to the FDA, and they're unaware of the claims. In fact, the FDA requires the standard disclaimer on such devices: "This is not intended to diagnose or treat any medical condition..." -- which is not on the Amazon description. And it has never been "prescribed" by doctors because this DOESN'T REQUIRE A PRESCRIPTION! The TENS and EMS prescribed by doctors cost hundreds of dollars, and are programmed within exacting standards. On the other hand, I bet that this unit doesn't even tell you what frequency or amplitude to use. That is certainly the case with the 15+ units I tested.
4) Unlike many other models, at least this doesn't claim to be based on Qi, accupressure, reflexology or meridians (although programs like sole and waist show its true origins). Instead, it makes claims based on the Western modalities of TENS and EMS. Yet 6 programs have no correlates in Western Medicine. Basically, the programs varies the frequency and intensity in set patterns, sort of like morse code. It makes the sensations less boring but does nothing therapeutic for the soles, waist, joints, etc in terms of TENS and EMS. IN those legitimate therapies, a set frequency is applied throughout the entire session, although intensity is often slowly increased to the maximum of tolerance. It does n't go fast-high-slow-low-fast-low, etc.
Basically, these are fun to play with, and can even feel pretty good. But don't expect any real clinical benefits like you would get with TENS and EMS.