Original heating trade vintage catalog for THERMAL UNITS MANUFACTURING COMPANY. Main office and plant was located at Pershing Road and Loomis Street, Chicago, IL. Manufacturers of Cast Aluminum Surface Heating Elements, Cooler and Air Conditioners. Disbound from a large 1931 builders heating catalog, this unique old one page technical specifications brochure would display wonderfully matted and framed. A marvelous addition to your retro heating equipment library. Slight damp stain on outer edge.