Original heating trade vintage catalog for GRINNELL COMPANY, was located in Providence, RI. Manufacturers of Thermolier Unit Heaters and Thermoflex Heating Specialties. Layouts Types and Models, Dimensions, List Prices and Weights for Thermolier Industrial Type and Factory Type, Application of Velocity Nozzle List Prices, Performance Curves, Tables of Capacities, Connections, Electric Wiring Diagrams, Automatic Control, Motor Specs. Disbound from a large 1931 industrial heating catalog, this unique old thirty-eight page technical specifications brochure would display wonderfully matted and framed. A marvelous addition to your retro heating equipment library. Pages are detached and may contain a small amount of residual glue on edge. Slight damp stain on outer edge.