Derkang New Air Stability Wobble Balance Rehab Cushion / Wobble boards / Wobble cushions / Rocker Boards / Tilt Boards/ Inflatable Wobble Cushion / Balance Pad / Ball Cushion Confetti / Stability Disc - Pump Included Improves posture, balance, stability and agility. Extremely strong vinyl that holds up to 400lbs One side is ridged to prevent sliding Rounded design provides greater instability.