The D'Addario Varigrip is designed to enhance the strength and dexterity of your fingers, hands, and forearms. It features an ergonomic design with adjustable tension for each finger. The reversible molded grip reveals simulated strings to help maintain finger calluses when you're away from your instrument. It's the ultimate conditioning tool for musicians. Note: Varigrip is an exercise product. Stop use immediately and consult a healthcare professional if you experience pain or discomfort while using it. Excessive use may cause pain or injury.