... appointed forwarder Usage: mainly for sports like tennis, golf, basket-ball, table tennis, badminton, bowling, rowing, rock-climbing ,basketball, motocross, ... a rotational wrist movement and to keep in sync with the spinning of the ball. Roller ball doesn't need batteries, is only ... LED bulbs light up when the ball is in motion. GENERAL PRECAUTIONS -Do not drop the ball on hard surface at any time ...