Designed to support a mattress, a box spring consists of a wood frame filled with either springs or a metal grid. The box spring is encased in fabric and placed beneath the mattress on a bed frame.

Most traditional or collapsible metal rail bed frames require a box spring because they're designed to hold one. Without one, they don't provide sufficient support for the mattress.

Underneath the stylish frame, there’s a durable wooden slat system that provides ample mattress support (no box spring required), similar to the Thuma Classic Bed and Saatva Valencia.

A box spring is an upholstered bed frame that supports and elevates a mattress. Traditional box springs have wire coils, but modern ones will have horizontal slats made of either wood or metal.