Grease nipples; junctions of metal for pipes; steel tubes; tubes of metal; elbows of metal for pipes; branching pipes of metal; drain traps being valves of metal; collars of metal for fastening pipes; clips of metal for cables and pipes; water-pipe valves of metal; valves of metal, other than parts of machines; common metals and their alloys; small items of metal hardware, namely, metal fittings for compressed air lines, metal pipe connectors, metal pipe couplings, spacer brackets of metal, m...