... centrifugal force & inertia like a gyroscope. It is powered by rotating the wrist. The speed of rotation can reach over 12 ... sports like golf, tennis, squash, cricket, badminton, baseball, bowling, basket-ball,, motocross, mountain climbing.2. Increases strength in fingers, wrists, hands ... of silicone rubber on the surface of the ball. That can prevent the ball from sliding down to the ground, and the ...