The CanDo Wrist/Forearm Exerciser improves flexion, extension, pronation, supination, as well as ulnar and radial deviation in the hand and wrist. Use the semi-spheres and handles together or use the semi-sphere individually. Mix and match the different sized handles and semi-spheres to find the right fit. This set comes with 3 semi-spheres and 3 handles. Each handle and semi-sphere come in a different size and color (X-Small ? Black, Medium ? Green, and X-Large ? Yellow).