Products that use electronic muscle stimulation, or EMS for short, like the ab rocket abdominal trainer have become hugely popular in recent years as these items are being used by people who are slightly overweight and want to slim down. They are also used by those who want a six pack abs stomach.  Getting rid of the fat and tightening their abs is the goal of many people who buy these devices.  The machines are simple to use and can be left on while a person is doing their daily routine.
Wearing an abs belt is one way of using electronic muscle stimulation to tone the abs.  It is fairly discreet and can be worn under your clothing.  This means it can be used while you are engaged in other tasks such as driving or working.  These devices are very common in the training room of many different sports teams.  When a professional sportsperson is injured and is unable to train, these products keep the body and muscles ticking over.  That means that there is some evidence that the machines will be able to help a person build some muscle since it has worked for rehabbing athletes.
When a person straps a belt to their waist they begin to make their abs exercise with a low frequency pulse of electricity that keeps the abs moving without a person noticing.  The impulses are generated by an electronic device and delivered through terminals or electrodes to the skin, directly on the muscles to be stimulated. Before long, the machine becomes another piece of forgotten exercise equipment even though it seemed like a good idea at the time.  Because the machine is no longer in use, it is not able to help a person get a set of six pack abs and they just stare in the mirror and dream of what might had been.
There is no doubt that this method does work to a degree.  However, for the serious athlete or bodybuilder these impulses can be compared to a weak muscle contraction.  These products can be beneficial for rehabilitation purposes such as when athletes are recovering from injury and are unable to undergo full training.  Instead of wasting your time and money buying one of these devices and putting it on every day, use the time to do a simple workout daily. It could be a much simpler process in the end.
Many people have made the mistake of assuming that electronic muscle stimulation will meet their goal of losing weight fast- and will give them the body of their dreams while sitting on the sofa watching their favorite television show.  This is wishful thinking and exaggerates the effectiveness of these products.  There is some benefit from the EMS machines but if a person has a goal of six pack abs they need to include the proper diet with a proper workout and the machine to achieve their goals.  You simply cannot get a trim and fit body without putting in the effort.
People do wake up suddenly and have a set of six pack abs.  It requires time and effort even if a person uses a machine like the ab rocket abdominal trainer, they still must monitor the food they take in and the amount of physical activity that they get on a regular basis.  But if a person is able to get the exercise and watch what they eat, there is hope.  A pieces of equipment that works out the muscles when they would otherwise be idle is something that can be useful.  If you are able to make you television watching time a time to use the machine, it can help.  Unfortunately, the results will not be the same as they could be.