All Steel Construction All steel high-rise. Combination of top spring, pop-up unit and tubular metal arms in one complete package that saves you money. Larger Than Queen Size Total Sleep Surface This 33" wide model can give you about 64"x75" sleep surface when you bring up the lower unit. That's larger than a Queen Size bed! (Poly Deck Models also available, please inquire.) Mattresses Stay Even with Each Other The Trundle Beds and High-Rise Frames are both 15 1/4" high so mattresses of equal thickness stay even with each other, and when side by side create sleeping area larger than a Queen Size bed.