This complete support system for your mattress replaces your current metal frame and box spring with a much more user friendly option. Excellent strength and durability, easy to bring home and set up, plus 14" of under bed storage! This affordable mattress support system is 100% steel construction and will conveniently and comfortably support your mattress while providing more than double the storage space found under traditional box springs and frames. Completed mattress support system-Replace old frame & box spring. Easy to assemble - in minutes - no tool required. super strong - 100% steel construction. 14" High-Storage space. Size: Twin 39" x 75" x 14".