Pressure Relief AIR SEAT CUSHION SELF INFLATION The air cushion is designed to quick self-inflate automatically and no hand pump required Open the air valve the cushion self inflates 36 air cells are filled with elastic foam cube From the compression state to the deployment, the foam rebounds to suck in the air. It supports self-adjustment the air pressure, simply open the valve let the air out and close valve to suit your comfort Lightweight, Portable, Convenient, Easy Installation It is suitable for wheelchair, car seat, office chair, taxi/truck driver, train and airplane long travel. Cushion material:TPU+Foam Cover material: Nylon (Air permeable & Anti-slip)