Air Layer CushionUnit : Each Overview The Air Layer cushion features a block of visco elastic foam that conforms to the buttocks, redistributing pressure and an 'air layer' to reduce heat transfer. CUSH AIRLAYER 43 43 5 Product Features The cover is PU multi stretch, water resistant and vapour permeable with welded seams, a 270 zip with protective flap Top cover has a white inner substrate to assist in identifying signs of cover damage and strike through Product