Original electrical trade vintage catalog for BLACKHAWK MANUFACTURING COMPANY. Main office and factory was located in Milwaukee, WI. Manufacturers of Porto-Power tools and equipment, used for installing electrical pipe and conduit. Hydraulic knock-out punch, benders, electrically driven hydraulic pump are shown. Disbound from a large 1951 architect construction materials book, this unique old one page technical brochure would display wonderfully matted and framed. A marvelous addition to your retro electrical tools and equipment library.