One frame that adjusts to twin, full, queen, king or California king, with a center support rail so bigger mattresses do not sag. The W. Silver Universal Frame is the heavy-duty version of their Standard Bed Frame: 1.5 x 1.5 inch angle iron side rails, 70 inches long, cut from high-carbon steel remanufactured from retired US railroad rail. Six heavy-duty locking legs and a head-to-foot 2-inch center support carry the load across the full width of a king. Key-slot cross-arms with spring clips snap together with no tools, so setup takes about five minutes. The legs ride on 1.75-inch rug rollers that move easily on carpet. 100 percent made in America. Frame height is 7.5 inches, and width adjusts from 38.75 inches (twin) to 76.5 inches (king). Pair it with a box spring or foundation, add headboard brackets if you want to bolt on a headboard, and it works in any bedroom in the house.