Our IBZ Series beds are made with 16 gauge 1.5" round tube uprights and 1.5" oval cross supports. Each end has hook plate receiving pins welded into place to allow the spring to sit snuggly on the outside of the ends; this helps with saving valuable living space. Bed ends come with nylon caps and are easily bunkable with added stacking adaptors and can be broken down to store compactly if not in use. Uses a No Sag Sinuous Spring, so no boxspring needed. Fully powder coated in black, made in the USA. No tools required. 400 lb. weight rating.