Full to Queen Converter Rail, Hook-on with 3 Center Supports Use queen size bedding on your full size bed. Three center supports for extra support at each end and center. Converter rails accommodate the width of queen bedding: The rails use 4 durable "L" brackets to accommodate the extra width of a queen size mattress! Converter rails are the length of queen size bedding: The usable space on converter rails measures 82" - 83" long to accommodate the length of queen size bedding. Converter rails come with three adjustable height center support legs that provide the proper support for a queen size mattress. Each leg adjusts up to 11" tall.