Balustrades of metal; Ducts of metal for ventilating and air-conditioning installations; Ducts of metal for ventilating installations; Metal construction materials, namely, exhaust vent hoses for external ventilation of furnaces, heaters, stoves and boilers; Metal expansion joints for piping and ducting; Metal roof vents for heating, cooling and ventilation in residential and commercial buildings; Metal shelf brackets; Metal vent cover for HVAC ducts; Metal vent covers for roof deck protrusio...