Very good day bed I put an 8" memory foam mattress on the bottom (trundle) and a 9" memory foam mattress on top and those sizes seem to be perfect. Trundle is not on rails/connected to the main frame, so you can remove the trundle if you'd like and still have a fully functional twin day-bed. Can be assembled solo, but is EXTREMELY heavy (takes 2 adults to move inside after delivery)

Overall nice quality.