Planet Waves Vari GripDesigned to develop and maintain the strength and dexterity of your fingers, hands, and forearms, the Planet Waves Varigrip features an ergonomic design and variable tension that is customizable for each individual finger. The reversible molded grip even uncovers simulated strings to help develop and maintain finger calluses when you are away from your instrument. Planet Waves Varigrip, the ultimate conditioning tool for musicians.