Brand Name:powerball Type:Wrist Power Ball Size: 7.5x6cm Function:Comprehensive Fitness Exercise Product Description Using a Wrist Exercise Ball is the most effective and convenient device to increase muscles strength in your arm, wrist and hand. A great exercise machine for musicians, typists and sports lovers, the Gyro Wrist Exercise Ball brings gentle and non-impact relief to Carpal Tunnel Syndrome, Repetitive Strain injury, tendinitis, arthritis and all wrist related ailments. Just using the 250Hz Wrist Balls for 5 to 7 minutes a day is enough to make a big difference! Strengthening the muscles in your wrists, hand and arm will help your perform at your best! The Gyro Wrist Exercise Ball is easy to carry around with you so you can use it in the office, on holiday and at the sports club as a warm up. Product Use Challenge(Wrist ball cordless start):Hold your left thumb tightly against the edge of the case (be careful to apply it tightly) and quickly wipe it from the inner surface of the ball! This is a quick wipe that will give the ball a great acceleration. This acceleration is enough to make you turn the ball to the light, and after the light is turned on, it's simple.