You must do cruches along with it in order to increase the size of your abs.
I would say that the only benefit from the ab machines would possibly be the localized fat reduction (which is highly debated) due to long extensive muscle contractions day after day.
But, if the machine actually works like electric shock, then I would say that it would be a good addition to diet, cardio, and crunches.
Does the ab enegizer have a website.
Nautica