Features: How To Use: 1: Both thumbs, direction arrows,The resistance is the greatest and the core cannot roll. 2: Hold the ball with your left hand, hold the ball with your right hand, and aim your palm at the bottom of the ball. 3: put down the ball core with the left hand, the ball core rotates 4: Feel the strength of the ball back and wrist, practice 20-80 times. 5: Pulse intensity, continue normal rotation. Describe: The Powerball exercise is completely isometric, so it complements any training method. Powerballs work the arms in a way that regular isotonic (free weight) exercise training cannot, and engage a higher percentage of muscle fibers in a shorter amount of time. If you want to improve your wrist, grip and arm strength, then wrist training balls are perfect for you introduce: * A tremendous strengthWith a maximum possible rev of over 12,000 rpm, it can generate drag of up to 32kg. It's the ultimate in wrist exercise equipmentslow rotations for gentle recovery, or fast rotations for forearm exercises in 60 seconds or less. * good coach Whether playing drums, piano, saxophone or guitar, musicians need to maintain strength, coordination and dexterity in their fingers and hands. Powerballs help with agility, speed, accuracy and stamina - if you can make music, Powerballs will help you play better. Product Description: 1: Stainless steel chrome-plated shell 2: Automatic start 3: Generates up to 61kg 4: Enhanced Repair