Original heating trade vintage catalog for GRINNELL COMPANY, was located in Providence, RI. Manufacturers of Thermolier unit heaters, hangers. Piping connections, dimensions, condensed capacities and conversion table provided. Disbound from a large 1936 industrial heating catalog, this unique old twenty-four page technical specifications brochure would display wonderfully matted and framed. Nice cover graphics. A marvelous addition to your retro heating equipment library. Pages are detached and may contain a small amount of residual glue on edge.