21 ELECTRICAL EQUIPMENT-NAMELY, COAXIAL CABLE; COAXIAL TRANSMISSION LINES; TRANSMISSION LINE FITTINGS-NAMELY, COUPLINGS, [NIPPLES,] ELBOWS, CONNECTORS, AND JUNCTION BOXES; TRANSMISSION LINE [INSULATORS AND] TERMINALS; ANTENNAS; [PHASING NETWORKS, INDUCTORS FOR ANTENNA TUNING; AND TOWER LIGHTING EQUIPMENT-NAMELY, WARNING LIGHTS]