Titan Fitness 55cm Exercise Stability Ball w/Base Chair Combo Gym Yoga Sports Usage: Place balance ball inside the ball base to keep it from rolling around when exercising on the floor;Sit on it at work or home, lay down and stretch on it, or do Swiss crunches or one of many other exercises Design: 1-piece construction, no assembly needed; Adds less than 1" to ball height The ball's material is comfortable, durable, easy to inflate and adjust, and odor-free. Weight capacity is 300 lb. Versatility: Can be used together as a ball and base for sitting at a desk or exercising; Holes on the side allow you to use straps or bands with your workouts; Works great as ball storage system Durability: Solid plastic base won't slide or crack; Ball is made of thick elastic PVC that will maintain its shape Many Benefits: Stretch on this to improve your flexibility and reduce lower back pain, improve your posture and develop core and ab strength by sitting or exercising on it.