Shaped fittings for furnaces; furnaces, other than for laboratory use; gas burners; kiln furniture [supports]; heating elements; hot plates; casting nozzles for furnaces; sliding nozzles for furnaces; nozzles for furnaces; sliding nozzle accessories for furnaces; casting nozzle exchangers for furnaces; porous plugs for furnaces for blowing gas into steel ladles or steel refining vessels; industrial furnaces; ceramic shelves as accessories for calcining kilns for industrial purposes; ceramic s...