The Dynaflex Pro Sports Gyro Exerciser is really a very curious device, its also known as a powerball anyone heard of it? well, the idea behind this gadget is that it will strengthen the lower part of your arm and your wrist. It does this using a sphere that spins at up to 20, 000 RPM (revs per minute) and by holding the ball and rotating your wrist the speed will increase. Its very hard to explain, you need to try it out yourself to understand.
What I can explain is how painfull this is, imediatly you will feel a strain on your wrist and the longer you go for the worse it gets. I use my powerball for playing squash and after a week of using it I can already hit the ball with much more power. The Powerball can also be used for Tennis, Baseball, fencing or anything else that uses the wrist. If you are in to any of those sports this is a must have.