BPL Air Mattress is an alternating mattress replacement system designed for prevention of pressure ulcers. The product works by sequentially inflating and deflating the alternate air bubbles. The inflated air cells provide pressure to support the user whilst the deflated cells provide relief for the skin above them. Features Pure copper compressor Medical grade PVC Extra End Flaps Auto-Adjusting Air Bubble Alternating Pressure Therapy Low Noise Operation Pressure Indicating Knob Anti-Vibration Metal Hooks