The patented Gripmaster is the only hand exerciser in the world that exercises each finger individually for optimum conditioning of the hand, wrist and forearm. <p>Challenges each finger individually using patented spring-loaded finger piston technology</p> <p>Greatly improves hand, wrist, and forearm strength</p> <p>Used by professional athletes and top fitness trainers worldwide</p> <p>Fits in your pocket. Workout ANYTIME, ANYWHERE!</p> <p>X-Light is recommended for seniors and children 12+</p>