TheMovin' Sit&Movin' Sit Jr.are inflatable dynamic air cushions which activates intrinsic trunk muscles to support the spine. The wedge shape encourages a seated posture with a forward pelvic position and the movement makes the user feel off balance if not sitting correctly. The child size version theMovin' Sit Jr.is 10" X 10" and fits perfectly in elementary school desks and other chairs. This inflatable wedge seat encourages static anatomical seating while mimicking the dynamic seating motion of a therapy ball. It is great for kids with poor posture and those who have trouble sitting still. In particular, kids with ADHD and/or Sensory Integration Dysfunction will benefit from theMovin' Sit Jr.. It can also be used upright in any chair as a back support or on the floor. Adjust inflation to comfort level. Size&Price:Movin Sit Jr.- 10" x 10" = $24.95Movin Sit - 13" x 13" = $32.95Please allow 5 - 9 days for delivery.