Essential hand and arm strengthening tool for all musicians looking to achieve a competitive edge during practice and/or performance. With the Dynaflex, you get an all-in-one tool that will exercise and condition hands, wrists, and forearms while increasing hand speed, coordination, and improving endurance. Perfect for anyone who uses their hands—from guitar hand conditioning to drummers and even massage therapists and typists—the hand-held exercise ball has an internal Gyro Roto and users can start the Dynaflex with either the ripcord. Then simply move the ball in a back-and-forth motion to increase the speed of the Gyro. Working the Dynaflex all the way up to 13,000 RPM improves coordination and builds strength and endurance in the hands, wrist, and forearms.