The Practice Grip is a pocket-sized hand and finger exerciser by D'Addario that ideal to help brass and woodwind instrumentalists who use keys or valves. This conditioning tool is designed with light overall tension to foster proper, healthy finger motion, digital independence, and helps develop increased speed and dexterity. This patented exerciser allows individually adjustable tension to each spring-loaded piston for an isolated and targeted finger workout that no other hand exerciser offers. You can focus on a specific finger that needs strengthening. Great tool for any musician from beginner to expert. Finger, hand, wrist and forearm strength and conditioning will be helpful for anyone who plays piano, keyboard, guitar, bass, drums, flute, trumpet sax, violin trombone, cello, viola, etc. Ergonomic shaped to fit the palm of your hand comfortably. Develops and maintains strength, control, endurance, coordination, and dexterity. Pocket-sized, so you can warm up before you play, practice anytime, anywhere, even without your instrument. Recommended for warming up 15 minutes before playing.