My latest addition, Clary M. Tune patented wrench. Patent 1,733,288 issued October 29, 1929. The wrench was manufactured by Rex Engineering in Cincinatti, Ohio, Rex was established in 1928. Tune lived his whole life in the Tiptonville and Memphis, Tennessee area his whole life. This is the only one I know of per this patent. The wrench measures 9-inches long. As can be seen the patent number and patent issued date are hand stamped on the wrench, the Rex Engineering stamp appears to be a one-piece manufactured stamp.