Ducts of metal for ventilating installations; Magnetic alloys; Metal heating ducts; Ventilating ducts of metal; Metal construction materials, namely, exhaust vent hoses for external ventilation of furnaces, heaters, stoves and boilers; Galvanized steel sheets; Metal vent cover for HVAC ducts; Ducts of metal for ventilating and air-conditioning installations; Metal pipe couplings; Heating ducts of metal; Metal couplings for pipes; Pipe couplings of metal; Metal HVAC ducts