Helps in the prevention and treatment of pressure sores. High density, high resilient polyurethane foam provides excellent pressure redistribution. Cut-out design removes all pressure on the coccyx bone. Stretch nylon cover is comfortable, breathable and fluid resistant. Safety buckles keeps the cushion in place. Weight Capacity: 250 lbs. (16", 18", 20"); +500 lbs. (22", 24", 26", 28", 30") Warranty: 1 Year.