Crown Sporting Goods Tuff Grip Rubber Medicine Ball An explosive and kinetic alternative to traditional weights. Perform hundreds of exercises that work every area of your body and improve flexibility, coordination, and movement Add a medicine ball to supercharge basic calisthenics, or try rebounding for an active, exciting way to work your arms and core Crafted from tough, durable rubber and inflated with air. Add or remove air to achieve your desired level of firmness. Great for rebounding and other bounce exercises, unlike sand or gel-filled balls Rubber exterior is covered with hundreds of dimples so you can maintain a secure grip, even in the middle of an intense workout Choose a weight that's heavy enough to slow your motion, but not so heavy that control, range of motion and form suffer