Feature: 1. Strengthen Grip, Reduce Stiffness and Pain: Hand therapy exercise balls can increase the strength of fingers, hands, wrists and forearms, and at the same time reduce stiffness and joint pain by stimulating blood circulation 2. Useful for Physical and Occupational Therapy: These balls are useful for physical and occupational therapy, and also provide a sensory outlet for people with ADHD or autism 3. Progressive Resistance Level: The progressive resistance level allows the difficulty of each training to gradually increase with the increase of hand strength and grip 4. Relieve Stress and Anxiety: Suitable for athletes, musicians, office workers and students, which can relieve stress and anxiety 5. Grip Strength Training: Suitable for grip strength training for people suffering from arthritis, carpal tunnel, phlebotomy, grip strength and rehabilitation needs Specification: Item Type: Hand Exercise Balls Material: Sponge Color: Green, yellow, blue, pink. Package List: 4 x Hand Exercise Balls