Relieve back pain with better posture. BackJoy SitSmart is a safe and effective way to relieve lower back pain and improve posture. SitSmart automatically positions your body in correct posture for all-day sitting comfort and posture support. This simple posture corrector works in any type of seat, from office chair to car seats, even hard bleachers. Measures 13″ x 15.5″.SITSMART POSTURE PLUS / Comfortable waterproof covering for indoor or outdoor use.