GRIPMASTER is ideal for any athlete or musician wanting to develop hand strength, dexterity and endurance. GRIPMASTER isolates and strengthens each finger using spring-loaded finger piston technology. Quickly builds hand, wrist and forearm strength. Note: Hand specialists recommend lower resistance and more repetitions rather than higher resistance and fewer reps. Important: always exercise slowly and cautiously. If you experience any pain, stop immediately and see your doctor. Excessive use may cause pain or injury.