... : 275g 3. 30pcs/ctn Promotion! LED Energy Wrist Ball WithSpeedometer excersise ball! There is no any battery or electricity inside the ... by rotating the wrist. The faster we rotate the ball, the stronger the dynamic and torsion is produced. The ... like golf, tennis, squash, cricket, badminton, baseball, bowling, basket-ball,, motocross, mountain climbing.2. Increases strength in fingers, wrists, hands ...