Features 1、1. Strengthen your grip and rehabilitation training: On the one hand, the grip enhancement balls can train arms and wrists, strengthen hand exercises, and reduce joint discomfort. On the other hand, help the injured to carry out rehabilitation training, divert attention and change some bad habits and relieve stress. 2、2. Four resistance levels: The grip training balls set includes four balls, and the four resistance levels are: 28.7lb (yellow), 44lb (orange), 66.1lb (blue) and 77.2lb (green). Different people use different colors for different purposes. For example, the yellow balls can be used for children and the elderly. 3、3. Wide range of applications: The grip training balls is suitable for office workers who need to type for a long time, patients who need rehabilitation training after injury, and also suitable for people who love sports, such as rock climbers, wrestlers or softball pitchers. Suitable for children of all ages, adolescents, including the elderly. 4、4. Ergonomic design: The grip training balls adopts an egg-shaped design for a more comfortable grip. The ergonomic design can be used to exercise hands anytime, anywhere, whether at home, traveling or working. 5、5. Safe and easy to clean: The grip training balls is made of 100% high-quality silicone, safe, odorless and tear-resistant. It can be squeezed and rubbed repeatedly, and it can be restored immediately. It may become dirty after playing for a long time. At this point, you only need to rinse with warm water and detergent. After natural drying, wipe it like new talcum powder. Material: Silicone Size: 6.8*4cm Package List 4*Grip balls