Looks like it is both a TENS & a Muscle stim

[The ReliaMed 700 combines the benefits of both an Muscle Stimulator and a TENS unit in a single unit.

The TENS features are useful for daily pain control and management and the Muscle Stimulator feature is helpful with therapeutic relief of muscle spasms and re-education of the]

Here's a little more info on the types of electric stims -
http://www.vitalityweb.com/backstore...Stimulator.htm