Rails enclose every side of this 78" x 42" x 16" frame and a lockable door closes the 19" x 12.5" gap, so the sleeping area stays contained without a crib. The door has three settings: shut, open or taken off entirely once a child no longer needs it. Plywood slats over a solid pine wood frame support a twin mattress up to 8" thick, and the surface sits 3" off the floor for independent climbing. No box spring or foundation required. Net weight 26.5 lbs.