Discovery World Furniture Twin Over Twin Staircase Bunk Bed with Twin Trundle, Espresso Solid Wood Construction throughout the entire bunk bed The trundle can accommodate up to a 6.5" mattress The staircase unit comes fully assembled and comes set up for use on the left side of the bed but can be reversed to the right side during assembly All Discovery World Furniture beds are tested and certified to meet the ASTM 1427-07 regulations set forth by the Consumer Product Safety Commission Slat kit is included with the bunk bed making it mattress ready; No need to purchase a Bunkie board or box spring; Mattresses and bedding not included