Metal tubes for industrial air dryers being parts of machines; metal tubes for industrial seawater desalination units being parts of machines; metal tubes for evaporator being parts of machines; metal tubes for liquid coolers being parts of machines, namely, for oil coolers for engines; steam engine boiler heating tubes being parts of machines; tubes for vacuum distillation apparatus being parts of machines; air-cooled condensers and metal tubes for air-cooled condensers being parts of machin...