Product Description Size: 7.0 cm * 6.0 cm * 7.0 cm Color: blue, green, purple Material: ABS Package content: 1*wrist ball 1.Forearm Strengthener Ball A very popular wrist ball to enhanced grip endurance, wrist arm and other best weapon, and can promote blood circulation, strengthen the wrist ligaments reduce injuries. It is a very interesting sensation and definitely makes your forearm sore and gets the blood going. 2. Good for Health Efficiently rehabilitates wrist pain, humerus fracture, scaphoid fracture, head fracture, numbness in fingers, numb hands, fractured wrist, elbow tendonitis, broken bones, olecranon bursitis. Increases strength in fingers, wrists, hands, forearms, biceps, triceps, ligament and shoulders. 3.More Suitable for Sports Training, Wrist Workout Highly beneficial grip strength trainer for golf, tennis, climbing, cycling, basketball, cricket, martial arts and with improved playing performance for pianists, drummers & guitarists. 4.Motor Skills This certainly requires some fine motor skills in order to use. The dominant hand/arm was easily able to keep the gyro ball hand exerciser going, that it will help refine your fine motor skills in that non-dominant hand/arm.