Designed 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. Develops and maintains the strength and dexterity of your fingers, hands and forearms Variable tension provides customized conditioning for individual fingers Reversible molded grip uncovers simulated strings to help develop and maintain finger calluses for string musicians Perfect tool for pre-show warm-ups and maintaining conditioning when away from your instrument The ultimate conditioning tool for all musicians