The under bed storage drawers are built into a pull out trundle . the trundle can be fully extended and includes slats on the top Pine construction and veneers; solid structural pieces Trundle daybed expands from twin to king and back again When the bed is underneath: 44W x 80D x 25H . Bed pulled out dimensions: 80W x 80D x 25H . Bed pulled out and drawers open: 97W x 80D x 25H Mattresses are not included Weight capacity: 220 lbs. per bed when extended Meets all CPSC and ASTM standards for bunk beds For the day bed: We recommend two twin standard size mattresses; each mattress should be 4-6"H. Assembly required