18 inches X 18 inches. The Harmony Cushion is most effective for users who need a surface that reduces discomfort require postural support are at moderate to low risk for skin breakdown are concerned about weight of mobility system. Reduces discomfort. Stability/Ease of transfer. Increased mobility & function. Air floatation support pad may be cleaned with soap and water. Moisture-resistant machine-washable cover. Specially formulated polyurethane die-cut foam base polyvinylchloride AIR FLOATATION cushion overlay. Includes Harmony Cushion Base Air Floatation Cushion Overlay cushion cover operations manual pump and patch kit. Additional sizes available. Weight capacity: 250 Lbs.