I found this wrench in a tool box at our local flea market. It is five inches long, its open end is 1 1/4 inches wide, and its closed end is a 3/8 inch square. One side is embossed "SUPERIOR" with a "0" embossed to the left. The other side is embossed "PITTSBURGH, PA."
I don't know what this wrench was used for, or went with. Can anyone identify this wrench?