6 valves, not parts of machines, of metal or their alloys; valves of metal, not being parts of machines, including in particular industrial ball valves for mining and chemical processing industries; non-structural parts and accessories for industrial ball valves of metal for mining and chemical processing industries; all of the foregoing not including buckles of common metal, metal brackets for general use, pulleys, springs, nuts, double-end swivels, screws of metal, metal clamps, metal wheel clamps, structure joint connectors of metal