Waterbeds use a water chamber as the support system. Manufacturers offer two types of waterbeds: hard-sided and soft-sided beds. A hard-sided waterbed consists of a water chamber inside a rectangular wood frame. A soft-sided waterbed consists of a water chamber inside a rectangular frame of rigid foam, zippered inside a fabric casing. The water chamber is covered by padding or upholstery materials, which can include with various foams and fiber. Both types of beds usually rest on top of a platform. Waterbeds are designed to look like a conventional bed and fit existing bedroom furniture.