Original concrete trade vintage catalog for THE VORTEX MANUFACTURING COMPANY. Main office was located at 1978 West 77th Street, Cleveland, OH. Manufacturers of Dens-Tect, Par-Lock plaster key, pre-plastering treatments. The asphalt compounds used are manufactured under strict supervision and laboratory test are made of each batch. This unique 1931 old two page technical brochure would display wonderfully matted and framed. A marvelous addition to your retro architectural library. Pages are loose and contain small amount of residual glue on edge.