Customizable Waterproof Internal Dog Bed Cover Only Exterior and interior of the cover are all sides waterproof - Guaranteed !! Do you have incontinent problem with your dog/s? No worry, this cover will definitely help! 40"x28"x4" cover is made of 100% polyester woven fabric. The waterproof coating will hinder all moisture from passing through the cover. This internal cover uses Velcro as the cover fastener instead of conventional zipper that tends to break after few months of use. Wrinkle-free cover. Please contact me if you want to order any other size that is not listed in my inventory. This waterproof internal cover is custom-sizable. Please contact me for the size down custom cover. Custom size fee of $1 is applicable.