Original heating trade vintage catalog for WESTERN ROTARY VENTILATOR COMPANY, INC. was located at 9110 Monica Avenue, Detroit, MI, and also at 1720 East 14th Street, Los Angeles, CA. Manufacturers of rotary ball bearing and Forbes Syphonaire roof ventilators. Efficient at very low wind velocity and symmetrical in design. Unbound from a large 1933 architectural catalog, this unique old one page technical brochure would display beautifully matted and framed. Nice graphics. A marvelous addition to your retro ventilation equipment library. Slight damp stain on outer edge.