Product Description 1. Active sitting: ergonomic support and spinal alignment. Strengthen your core as you sit. 2. Versatile: Sit on it at work or at home, lie down and stretch on it, or do a swiss crunch or one of the many other exercises. 3. The material is comfortable, durable and odor-free. Made of elastic PVC that keeps its shape. 4. Easy to pump and adjust: Insert the pump to inflate. At first, the ball may not reach the stated size because the elastic PVC needs to stretch, so re-inflate after a few days to reach the maximum size; you may need to re-inflate occasionally. 5. Benefits: Stretch it to improve your flexibility and reduce lower back pain, improve your posture and develop core and abdominal strength by sitting or exercising it.