I saw the commercial and thought that it looked like it worked exactly like a "tens" (?) box. My dad had one of those after some muscular damage to his leg, it was meant to keep pain down by pulsing electricity. I used to play around with it when he wasn't wearing it and wasn't around, if I put one electrode on each side of my arm and cranked up the juice it would contract my forearm and bicep and make my arm bend at the elbow and I couldn't move it till I turned the power off it was kinda cool, I been thinking of ordering one of those just to play around with, and maybe to try and ease pain in my legs after heavy squats or presses.

As for "working out" with it I dunno, in theory you have to completely exhaust a muscle to the point of failure before gains are made. I remember this thing would make muscles contract hence my arm all bending up but I never felt soreness from it like I would after say working out or hauling around ammo at a gunshow all day. I kind of apply the "you don't get something for nothing" and "no pain no gain" to everything in life but esp. body buiding. hell it's only 40 bucks you'll at least get 40 bucks worth of use out of it making booby traps (not real ones not powerful enough but you can freak people out with it) and playing with it.