Fits twin mattresses, we opted for normal ones versus ikea padded ones and it worked great. Kids grew out of it, but is a good setup for little ones. Has a few broken weld beams in the spiderweb support frame, but doesn’t impact sturdiness. Pull out bed has wheels and just slides out for easy sleepovers, this one we did get the ikea mattress for. Mattresses are well... kiddofied or I would throw them in the deal. Main bunk bed is disassembled right now but the slide out is not.