CHALLENGE YOUR CORE Helps improve posture and strengthen core muscles through active sitting Adds challenge to your workouts by providing a plane of instability that forces muscles and joints to maintain your balance Aids with post-workout stretching to improve flexibility and range of motion DURABLE DESIGN Non-slip, ribbed surface for added grip Anti-burst up to 550 lbs. KEY SPECS Diameter: 22’’ (55 cm) Weight: 0.55 lbs. ADDITIONAL DETAILS Materials: Latex-free, anti-burst polyvinyl Includes easy to use pump and bonus exercise guide Intended for users 4’11’’ – 5’3’’