YogaAccessoriesTM yoga balls are made from a durable vinyl, and are designed to support up to 600 pounds of pressure. The balls are shipped deflated, and can be inflated quickly and easily with a ball pump. Each ball comes with a free pump (one per order). Physical therapists and dancers use physio exercise balls in a variety of movements. Used in both yoga and pilates, these air-filled balls give support in poses such as backbends, hip openers and restorative poses. Ball Size Recommendations: Under 5"6" -- 55 cm 5"7" to 6"0" -- 65 cm Over 6" tall -- 75 cm