Lumex Select Convertible MattressThe Lumex Select Convertible Mattress provides outstanding pressure displacement and redistribution to assist in the prevention and treatment of stage I through IV pressure ulcers. Features: Closed System (Static Air) can quickly convert to an Alternating Pressure Mattress Eight non circular cylinders prevent "rolling" or "gapping"* and are fully enclosed in a fiber mesh sleeve and jacket Air control unit is simple, quiet and set at the optimum 10