I am looking into buying one of these belts, I have not heard of the Flex belt before, but of course of the Contour belt seeing as it is plastered all over the TV. One thing that has always stopped me from purchasing one is, the rumor of these EMS systems cause cancer later in life. Has any one ever heard of this? I really want one, I am a big guy 6′ 5 1/2″ 330lbs size 18 shoe. Now you can paint a picture of my size. I am always exercising, running, walking, push ups, sit ups, curls ect. I have a lot of power, but not a lot of muscle tone. I eat rather healthy, and junk food on occasion. Any tips from any one on the best abs belt to use? Contour or Flex Belt? I need to stay in shape for my career. Thanks to all for sharing.