covers and frames made wholly or principally of cast iron or common metals for manholes, manholes, grilles, gullies of cast iron, modular covering of cast iron for gutters and hoppers, cast iron for use in hydraulics, sanitation, road systems and buildings

covers and frames manufactured integrally or essentially from common metals intended for manholes and similar structures; component spare parts

Metal Covers and Frames for Manholes and Similar Access Places and Parts and Fittings for Such Covers and Frames, All Made Primarily of Metal