The NoDec A is an alternating pressure system for the prevention of pressure ulcers for patients at medium to high risk. It is also an effective therapy for pressure ulcers up to grade IV. The NoDec A consists of 17 lateral cells that are inflated and deflated with air in regular cycles. Two side formers are constantly inflated and provide stability at the sides. There is also a Static mode which lasts for two hours with an automatic change into alternating pressure. If the NoDec A is used with the optional foam inlay, the NoDec A mattress can replace the bed mattress. The bottom of the NoDec A mattress can be opened at two sides with a zip and the foam inlay easily placed in. If the NoDec A mattress replaces the bed mattress and bed rails are used, then the system meets the bed rail standards according to DIN EN ISO 1970. The mattress replacement / mattress overlay is secured to the bed with strong easily adjustable straps. The system provides for automatic pressure adjustment for a patient weight up to 160 kg. Transport mode is achieved by automatically closing CPC connectors. There is separate deflation of the side formers with an additional CPC connector for the ease of patient access.