PsmGoods 3 Grip Hand Finger Forearm Strength Trainer 3 Levels Exerciser Gym 1.high -quality environmentally friendly silicone manufacturing , with soft, non-cracking , long life, does not irritate the skin and so on. 2.easy to carry , and enhance Zhang Li , referring to the force . 3 .the beginning of the exercise , silicone grip ring on the palm of her hand , the hand of the sheets together will follow silicone grip elastic force circle , a small amount of exercise fist action. Adhere to two or three minutes , palm to finger will feel soreness, fingers open at this time , do stretch outward from the fingers to the fingertips have been fully exercise. 4.Material: environmental protection silicone