metal building materials; namely, angle irons, building boards and panels of metal, non-electric cables, metal pipe couplings and joints, pipe clips, doors of metal, door casings, ventilating ducts, flashings, flooring of metal, knobs, latches, linings and claddings of metal, moldings of metal, sheets of metal, windows of metal, and wire; portable metal buildings; metal hardware; namely, bolts, nuts, metal cotter pins, hooks, nails, rivets, and screws; metal pipes; and metal tubing