Comfort Disc is the new and revolutionary way to get fit – just by sitting better! You place it on any chair to strengthen your abdominal muscles and burn calories – even when watching TV or working at your desk! The clever construction forces your core muscles to work, without any special effort. It’s the safe and comfortable way to get in better shape! Comfort Disc has a chamber of air designed to move when you sit on it. It also helps you to achieve a better posture and reduces the stress on your lower back! You save time and get amazing results – faster and easier than before! In your own home – or at the office! Sitting on it for 8 hours a day equals several workout sessions per week! Adjustable inflation for comfort control and to adjust degree of difficulty. Supports up to 300 lbs. Diameter approx 13”. Textured surface prevents slipping. Comfort Disc makes the most of all your “sitting time”! Not a medical device. If you have back problems or other health issues, please consult your doctor. Results will vary.