6
Pipes, tubes, fittings for pipes and tubes; couplings, connectors, valves, joints, clamps, adaptors and repair clamps all for pipes and tubes; gaskets and seals for all the aforesaid goods; all made wholly or principally of metal; parts and fittings for all the aforesaid goods
17
Pipes, tubes, fittings for pipes and tubes; couplings, connectors, valves, joints, clamps, adaptors and repair clamps all for pipes and tubes; gaskets and seals for all the aforesaid goods; all made wholly or principally of plastics, rubber or synthetic rubber; and parts and fittings for all the aforesaid goods
19
Pipes, tubes, fittings for pipes and tubes; couplings, connectors, valves, joints, clamps, adaptors and repair clamps all for pipes and tubes; gaskets and seals for all the aforesaid goods; all made not of metal; and parts and fittings for all the aforesaid goods