Harbinger Ergonomic Grip Strength System with Progressive Resistance Levels | Set of Three GripsThe Harbinger Ergo grip strength system is uniquely designed for fast and efficient whole hand and individual finger strength building at home or on the go. The ergonomic donut shape fits the natural shape of the hand, minimizing the risk of dropping the grips, and silicone provides a secure, non slip surface for excellent control while strengthening the hands and fingers. The shape is designed to accommodate a range of hand sizes and work well for