Power Putty is a flexible silicone rubber that can be squeezed, stretched, or pulled to do twelve different exercises for strengthening all the muscles in the fingers and hand. Power Putty is the most effective hand strengthener, and it's fun to use! Other hand exercisers like springs and balls work only the muscles that close the hand. Power Putty strengthens all the muscles in the fingers and hands to develop strong, quick hands while improving dexterity and flexibility. Recognized by golfers, tennis players, water skiers, rock climbers, and all serious athletes as the most effective way to develop superior hand strength and endurance. Recommended by hand surgeons, therapists, and professional sports trainers for the prevention and rehabilitation of injuries. Helps to relieve stress and tension. Available in four resistance levels to meet your individual needs and level of strength.