I would just like to know peoples opinion on this:

How effective is this products like thiis ? Anybody who also has used this before , how would you rate it ?
I have one, bought it for 1 cent on ebay a few years ago......

Actually stimulates the abdominals very well and gives it a good workout at the high level but crunches are much better overall. Not only that, that device is pretty painful actually and it had my stomach in knots for days.