about this project Material: The exercise ball is made of high-quality thermoplastic rubber (TPR) and food-grade silicone, which will keep its original shape after repeated squeezing and stretching. PORTABLE SET: This set is perfect for anyone to exercise their hands anywhere, whether you're sitting at home watching TV, walking, or taking a lunch break in the office. 3 levels of resistance: easy, medium and heavy. Resistance 33Lbs (yellow), 40Lbs (orange), 66Lbs (blue), different resistance levels for beginners and advanced users. Great for progressive training. Function: Improve hand strength, finger dexterity, joint flexibility by using hand grip ball and finger stretcher. These can also be used to aid in injury recovery, relieve muscle pain and relieve stress Wide application: The hand exerciser kit is perfect for athletes who play baseball, tennis, golf, boxing and fitness, for outdoor adventurers who like rock climbing and bodybuilding, for musicians who play piano, guitar, bass and violin, and for those who have daily pressure. Features: 1. The ball can strengthen the strength of your hands, forearms, fingers through simple exercises, and relieve the stress of daily life 2. Keep your hands, fingers, wrists and forearms stronger while relieving stiff joint pain and increasing range of motion and flexibility. 3. Release daily stress for people who sit and work for a long time or have daily stress. Suitable for teens and all ages above Package Included: 3 X Three Level Resistance Hand Therapy Exercise Balls