Original roofing trade vintage catalog for THE BY-PRODUCTS COMPANY. Main office was located at 2509 50th Avenue, Bladensburg, MD. Manufacturers of Rite-Lite acrylic skylights with or without insulated curb. Products include Magna, Circular skylights, Vent-O-Lite, Roof Scuttles and Pul-Air Stationary Ventilator discussed. Unbound from a large 1958 architectural catalog, this unique old four page technical brochure would display beautifully matted and framed. Nice cover graphics. A fantastic addition to your retro roofing construction library. Pages are detached and contain a small amount of residual glue on edge.