MediChoice offers a variety of wheelchairs seat cushions, including this 17 by 17 inch Air Lock Seat Cushion, which is made of durable, antibacterial and flame-resistant vinyl. The cushion, which comes pre-inflated, provides support and pressure relief. The cushion is valved which makes for easy inflation and deflation when necessary. Safety tie straps hold the cushion in place. The cushion has a weight capacity of 350 pounds.