Unique Shape - Our therapy balls are a unique egg shaped, which fits well in the palm of your hand. They are also made of a soft, easy to clean thermoplastic rubber unlike other hand exercisers. They are lightweight, hypoallergenic, and reble. Increase Hand Strength and Flexibility - Our therapy balls come in 4 resistance levels, allowing you to slowly increase your hand strength over time Each resistance level is colored coded, making it easy to keep track during an exercise session. We even included an exercise guide to help you get started. Prevent Stiffness & Reduce Joint Pain - These hand therapy exercise balls help increase blood circulation throughout the forearm, wrist, and hand when used correctly. This helps reduce muscle stiffness and joint pain. They are very useful for physical and occupational therapy, rehabilitation, those with arthritis and carpal tunnel. Reduce Anxiety/Sensory Outlet - These therapy balls can be used as stress relievers and as a sensory outlet for those with ADHD or autism. Unlike other hand exercises, ours comes in a fun, colorful, unique shape. The textured surface adds more sensory input than many other traditional stress balls. Great for - Athletes such as wrestlers, those with carpal tunnel syndrome or arthritis, teachers, counselors, phlebotomists, students, people recovering from hand surgery, physical therapy, ADHD, autism, anxiety, and anyone who has generalized muscle tension in the hands, wrists, and forearm.