Product Size: 12*6*9CM color: blue Material: TPR Package content: 1*grip ball 1. There are stabs on the surfasce of the handle and they play an important role in massaging the hand muscles and promoting blood circulation. 2.The grip strengthening ball can promote recovery from hand injuries, improve the strength and flexibility of the hands and fingers. 3.This grip strengthening the ball is exquisite and compact that you can take the ball out of your pocket or satchel anytime you need. 4.The main function of the hand tonic is to relieve tension in the hands and arms and allow joints to become supple. You can use the ball to relieve your stress. 5.This pressure ball has 4 finger holes to allow your hand to fix firmly.The size is suitable for most people, especially for athletes, and musicians..