Stress Ball, MaxMall Hand Exerciser Grip Strengthener Balls, Set of 3 Resistance Levels Squeeze Ball Composed of thermoplastic rubber (TPE), Durable, high-elastic, feel flexible,with a textured surface for a perfect fit in your hands. Special design: Can be repeatedly compressed without losing its shape, can exercise the head muscles and flexibility of the fingers. 3 different resistance levels:soft (yellow), medium (red) and firm (blue), find the perfect resistance for your needs. Grip Strengthening:Recovery training, prevents stiffness, increases flexibility, relieves joint pain, reduces stress and eases muscle tension, promote blood cycle. What we offer:3Pcs Grip ball, MaxMall provide you 12-month warranty and supply friendly customer service to all of you.