This low air loss overlay provides proven treatment success to patients at risk of pressure areas. The cost of this product enables it to be used as a semi-disposable overlay for single patient use, which lowers the process costs and increases hygiene. Micro-perforations on the overlay facilitate an improved microclimate and lying stability is improved due to the two-chamber system. Supplied with a vapour permeable cover. Suitable for the prevention and treatment of pressure ulcers up to and including level III on the Norton scale, and for immobile patients who use a standard mattress and rely on optimal cushion pressure distribution. Overlay height when filled is 110mm (41/4").