The Planet Waves Dynaflex builds and conditions hands, wrists, and forearms while also increasing hand speed and endurance. Simply start the rotation and then with a rocking motion, build up the gyroscopic speed and feel the burn. The Dynaflex allows you to achieve a competitive edge no matter what instrument you play. Planet Waves, part of the D’Addario family of brands, is known for innovative, problem-solving, quality musical accessories. Planet Waves offers a complete line of award-winning accessories including cables, picks, tuners, capos, straps, humidifiers, maintenance tools, and more.