Self-starting and Easy to Use :- Built-in automatic bouncing device, one push and release, you can easily start, the strength is free to grasp. Wrist and Forearm Exerciser :- Wrist force ball can be a good exercise for your forearm and wrist joints, help to build strong functional wrist and forearm, much better than holding tight squeeze. Well Made :- Sturdy exterior, rubber handle, metal ball core, non-slip silicone edge for safer. Wrist Cord Protection, Safe and Convenient :- You can use the wrist strength ball in a variety of occasions such as watching TV, walking, traveling, arm exercise, wrist recovery, etc. Please wear a special wrist cord when playing to prevent excessive force and throw out; Hand grip is moderate in size and easy to carry. Suitable for People Sports enthusiasts :- through the wrist ball exercise to make it more tension and more powerful; Office workers - through the wrist ball exercise can be away from sub-health or ease the discomfort brought by the mouse hand; Students-to promote bone development, enhance grip strength, wrist strength, arm strength and finger flexibility; Wrist injuries - through the wrist ball exercise to speed up the flexibility of the healing hand injury.