Mainstays Twin Over Twin Wood Bunk Bed (Black) Easily converts to two stand-alone twin beds. Designed to accommodate a mattress without a box spring. Only coil spring mattresses are to be used on both bunk levels; mattresses sold separately. Bed support slats are included. Guardrails are included. Features a ladder that can be installed in 1 location. Top bunk is designed for children ranging from 6 years of age to young teenagers.