rolled and cast metal building materials; namely, tubular, bar, angle, channel, I-beam, H-beam and plate stock, arches; rails; chains (except driving chains for vehicles); metal non-electric cables and wires; metal locksmith's work; namely, locks, keys, hasps; metal pipes and tubes; steel balls; metal nails and screws; metal coverings; namely, roofs, ceilings metal sheets and arch supports therefor; membrane-shaped metal coverings; metal structures; namely, welded-pipe assemblies; metal wire-...