BMX racers, motocross racers, enduro riders - anybody who goes "all out" on two wheels - share a fatiguing phenomenon known as "arm pump." The unique DynaGrip Gyro, which incorporates a specially designed motorcycle-like grip, helps you enjoy longer riders with less arm fatigue and arm pump. Imagine simulating the way you throttle up and down your bike while watching TV. Like all of the gyros in the Dynaflex lineup, the DynaGrip is powered by patented gyroscopic technology, and generates up to 40lbs. of resistance. Just rev up your gyro for improved grip strength, dexterity, range of motion, blood flow and muscle tone.