metal heating ducts; metal air conditioning ducts; ventilating ducts of metal; duct fittings of metal; metal pipes; metal pipes and metal fittings therefor; metal pipe fittings; metal pipes and fittings for residential, commercial, and consumer use

non-metal heating ducts; non-metal air conditioning ducts; non-metal ventilating ducts; non-metal duct fittings; non-metal water pipes and fittings for residential, commercial, and consumer use; pipe fittings comprised primarily of plastic; non-metal water pipes; non-metal pipe fittings