Billings Twin over Twin Bunkbed by American Woodcrafters Warmth with a slight industrial edge are the hallmarks of the Billings Bedroom Collection. Double up on sleep space with the Twin over Twin Bunk Bed. The classic mix of storage and style gives this bed universal appeal. Simple frame paneling and slat detail allow it to pair with a variety of other pieces. Double bed on the lower level topped with twin bed at the top. 13-piece slat roll mattress support systems are included with this bed. Tenon and mortis construction, a centuries old method of joining two pieces of wood together to provide strength and durability., Bed is constructed so the horizontal and vertical solid wood pieces interlock for strength and stability, Two rail positions to accommodate the optional trundle, Built in ladder, 13-piece slat roll mattress support systems are included with this bed., Meets Consumer Product Safety Commission and American Society of Testing and Materials safety standards