Enhance your workouts with a stability ball that helps you build back and core strength by adding balance and resistance to increase muscle activation. The ball comes in three different sizes to accommodate a wide range of different heights so you can find just the right fit for your body.The 55 cm ball is recommended for heights 5'0" to 5'5", the 65 cm ball is recommended for heights 5'6" to 5'11" and the 75 cm ball is recommended for heights 6'0" to 6'5". Each anti-burst ball comes with a pump for easy inflation to help you get started — or continue on — your journey to feeling and being your best self.