BackJoy SitSmart is an innovative sitting device that naturally relieves back pain by optimizing your sitting posture. Safe and effective to use, it automatically positions your body in correct posture for all-day comfort. Its patented design works by tilting your hips upright and comfortably “floating” your spine over the seat. and made of Comfortable waterproof covering for indoor or outdoor use. Great for office, car, bleachers or on the go. All SitSmart seats have the same posture-improving benefits, regardless of which style you choose. The only difference between the various SitSmart models is the surface material that covers the seat. Regardless of which style you choose, your SitSmart will position your body in correct posture for all-day comfort.