1、 Simple exercise: The grip training device is divided into three strengths (5 pounds, 15 pounds, and 30 pounds resistance), which can improve finger flexibility and grip strength for mountaineering, fitness, tennis, baseball, boxing, golf and shooting. It can relieve some tension and anxiety of guitarists, bassists, pianists and violinists. 2、 Scope of application: enhance hand strength, perform hand rehabilitation training, relieve stress, obsessive-compulsive disorder, autism, ADD/ADHA, muscle memory, etc. When using, start with the resistance ball with the least pressure, and the opening and holding of the hand should follow the elasticity of the ball. After 2-3 minutes, palms and fingers will feel sore. Repeated practice can effectively improve the strength and flexibility of the hand. 3、 Product material: completely safe for children and adults. The pressure ball is made of thermoplastic rubber (TPR), but it does not have a strong rubber smell and can be cleaned with water. Anti-drop design, don't worry about falling to the ground when using. It's okay if you accidentally get sand and fluff, it's easy to clean. 4、 Applicable occasions: The size of the sphere is ergonomic, and the diameter of the sphere is 09 inches. After holding the ball, all five fingers can be used hard and can be easily put into the pocket. Take it out when you need to squeeze. You can use it on walking, traveling (car, plane, bus), office, school, watching TV, talking on the phone or wherever you want to exercise. 5、 Package content: 3 kinds of grip balls with different resistances. Choose different intensities according to the exercise time. The finger tensioner can be used with the ball to practice the muscle strength of the back of the hand.