Original window trade vintage catalog for DAYTON GREENHOUSE MANUFACTURING COMPANY. (Formerly the T J Callahan Company). Main office and plant was located in Dayton, OH. Manufacturers of Window Operators. Products include direct-action window operators, hand & electrically controlled, for steel or wood sash. Series types 500, 700, 800, and 900. Unbound from a large 1931 architectural catalog, this unique old one page technical brochure would display wonderful matted and framed. Nice graphics. A terrific addition to your retro window operator library.