Mievida Anti Decubitus Air Bed alternating pressure mattress was designed to provide relief from bed sores and ulcers caused from prolonged bed rest. Equipped with 130 individually heat-sealed air bubbles for even weight disbursement and superior support. Designed to be placed on top of a regular bed mattress. It has air-filled channels that alternate filling up and decompressing to keep bearing weight off certain areas, and allows blood flow to reach different areas of the body of immobilized or weak patients who cannot shift their weight frequently. Product Features: Ultra Quiet Pump Durable & Waterproof Pad Easy to Set Up Pressure Sore and Ulcer Relief.