Electronic muscle stimulators are the latest craze.  The big questions is can they do what they say?   {The origin of these devices is necessary for someone to know what they can and can not do.}
Electric ab stimulators were originally used in medical rehab situations. They are designed to keep muscles from atrophying in situations where a limb must be immobilized. For example, if you broke your leg, the doctor could place an electrode on the muscle and use electricity to make it contract.  The contraction that was created kept the muscles from atrophying because they were not being used.
As far as building muscle, such as the ads like the ones for the ab rocket abdominal trainer on TV claim, this is not backed up by research because the level of electrical stimulation necessary to build up the abdominal muscles to what you see on TV would be extremely high, and thus very painful.
It is not unheard of that people will try to use a machine to get rid of the meat that is growing around their midsection.  In reality, the small muscle contractions produced by these belts burn about as many calories as the effort required to take the belt out of the box and put the batteries in.
The best way to get fit and trim is through a diet and workout plan and most of these devices include that suggestion somewhere in their sales pitch.  If a person follows that suggestion than they will get a fit and trim body.  If a person has a goal of losing weight fast then they need to do more than just strap a machine around their waist and although they might receive some benefits from using one of these machines they must commit themselves to a total fitness program to achieve the goals they want.
If that is true, how come so many people swear by these machines and say they are the reason they look the way they do?  There is some truth that the devices will exercise you ab muscles at least some.  If a person is not doing anything else to get fit and trim, than their body will react to even the little bit that occurs from using one of these devices.  It is simply a matter of something is better than nothing.  But it is not that much better.
A much better solution for working your abdominal muscles effectively is to do the unglamorous crunch exercise. It may not send electric shocks into your guts but it will get the job done. Crunches, even done properly and regularly, won’t burn fat but they will definitely tighten up your abs.
Is it worth spending the money on these machines?  Probably not as well as they claim to.  These companies are simply preying upon society’s desire for results without effort.  You should not fool for their trap.  If you want to spend your money on a machine like the ab rocket abdominal trainer, then do so with your eyes wide open and do not expect to achieve great results without putting in any other effort into modifying the way that you live.  In order to get a great body and keep it that way a person needs to get rid of the bad habits that they have.  It is the things that we did that created the problem to begin with.  The bad choices must be eliminated and good choices should be implemented or your body will not change.  That is something that is done in their head and no batteries are required.