Box-spring

A box-spring is a type of bed base typically consisting of a sturdy wooden frame covered in cloth, and containing springs. Usually the box-spring is placed on top of a wooden or metal bedframe which sits on the floor and acts as a brace. The box-spring is usually the same size as the much softer mattress which is placed above the box-spring. Working together, the frame, box-spring, and mattress make up a bed. It is common to find a box-spring and mattress being used together without the support of a frame underneath, the box spring being mounted directly on casters standing on the floor.