The Bergan Hammock Style Seat Protector comes in two materials to suit different needs. The Heavy Duty (HD) is constructed of durable, waterproof, 600 denier polyester and comes in gray, while the Deluxe (DX) is made from absorbent microfiber material with a waterproof backing and comes in gray. Both are designed to keep pets from falling off the seat while containing dirt and hair. These hammock-style seat protectors attach instantly to either the head-rest or car seat anchors. They fit all vehicle rear seats and are machine washable.