It works but not very well and they kind of burn your skin a little. The electronic shock imitates what your muscles do when you workout.

they some what work;

along with a reduced diet, which for unamed reasons will be low in fat, salts, sweets, and just about anything processed,
you would also have to do cardio blaster workout very frequently( maybe twice a day) along with areboic and anaerboic exercises,
along with a rapid increase in water consuption that you have probably never expereinced

so yea they work
and good luck with it

I do not suggest it. I purchased a version of one of those products years ago and while it did make me abs contact there was no resistance to make my abs stronger. In theory it is a great concept, but in reality there is no substitute for real abs workouts.
Personally i believe they are a waste of money. The companies that put those product out are thriving on people who want to get their abs will little work. Best investment is join a gym, get a personal trainer (if you think you need one) and eat correctly.