Smith & Nephew Allevyn Non-Adhesive Hydrocellular Foam Dressing 4" L x 4" W Square, Highly Absorbent, Trilaminate Structure, Waterproof Outer Film Layer. Smith & Nephew Allevyn Non-Adhesive Hydrocellular Polyurethane Dressing has a trilaminate structure that is comprised of a non-adherent wound contact layer, a hydrocellular core and a breathable outer surface. The outer, pink layer allows the formation and maintenance of a moist wound environment at the wound surface that helps to prevent eschar formation. The pink film is also waterproof and aids in the prevention of bacterial contamination. Highly absorbent, central, hydrocellular layer. Helps create and maintain a moist wound environment. Lack of adhesive allows the use of the most suitable retention method. Conformable and can be cut to suit various wound sizes and locations. Soft and cushioning, it provides excellent comfort. Can stay in place for up to 7 days. Easy to use.