ProSource Hand Grip and Wrist Strengthener &ndash; Resistance from 100-350 lb Metal Exerciser for Hand, Forearm, and Fingers USE ANYWHERE - Provides resistance to help develop muscles in hands, arms, wrists, forearms, and fingers for increased strength BETTER PERFORMANCE - A time-tested method for developing your hand grip for improved function and endurance in sports and weight lifting STRONGER GRIP - Great for improving daily function, such as opening and closing jars, or rehabilitation after an injury. DURABLE - Made with top grade, durable aluminum knurled handles and high quality springs for a long-lasting exercise tool 6 STRENGTH LEVELS - Choose from 6 different strength levels, or buy a few so you can easily progress: 100, 150, 200, 250, 300, and 350 pounds