Original door trade vintage catalog for THE R. C. MAHON COMPANY of Detroit, MI. Manufacturers of Rolling Steel Doors, Grilles, and Shutters. Specially designed interlocking slats rolled from copper bearing electro-galvanized steel, aluminum or bronze. Installed in the Pere Marquette freight Terminal, Detroit. Disbound from a large 1938 building material construction book, this unique two page technical specifications brochure would display wonderfully matted and framed. A marvelous addition to your retro architecture and engineering library.