Castings, foils, powder, and rolled, drawn or extruded semi-finished articles of aluminium or its alloys; Castings, foils, powder, and rolled, drawn or extruded semi-finished articles of copper or its alloys; Elbows of metal for pipes; Junctions of metal for pipes; Metal fasteners, namely, bolts; Metal flanges; Metal pipe couplings and joints; Metal pipes and metal fittings therefor; Metal pipes and tubes; Metal valves not being parts of machines