A mattress is a large, rectangular pad for supporting the reclining body, designed to be used as a bed or on a bed frame, as part of a bed. Mattresses may consist of a quilted or similarly fastened case, usually of heavy cloth, that contains materials such as hair, straw, cotton, foam rubber, or a framework of metal springs. Mattresses may also be filled with air or water.
Mattresses are usually placed on top of a bed base which may be solid, as in the case of a platform bed, or elastic, such as an upholstered wood and wire box spring or a slatted foundation. Popular in Europe, a divan incorporates both mattress and foundation in a single upholstered, footed unit. Divans have at least one innerspring layer as well as cushioning materials. They may be supplied with a secondary mattress and/or a removable "topper". Mattresses may also be filled with air or water, or a variety of natural fibers, such as in futons. Kapok is a common mattress material in Southeast Asia, and coir in South Asia.