Prevail Disposable Underpads, SUPER ABSORB, FIRST QUAL PROD, 23X36in Waterproof Chuxs. These disposable Prevail Underpads measure 23X36in and are used to protect your bedding and furniture from leaks. Prevail disposable underpads, often referred to as chuxs feature an Integra Mat. and new Dri-Bed protection. What this means, in layman terms, is that they are quilted withwaterproof moisture barrier and have bonded construction that reduces the top sheet from separaton and clumping. Prevail UP-150 underpads are super absorbent with a soft, yet strong, cloth-like top sheet and a flat seal around the pad. There are no plastic edges exposed to the skin.