M_Boats: Thingamajigs and Doohickies

Older M17 owners: If you have the tricolor running lights at the top of your mast, what do you call the thru-deck screw-in connection between the mast wiring and the boat wiring? Could a VHF coaxial cable also run through that same piece of hardware? If not, is there a different piece of hardware available that could be mounted in the same hole, but handle both the mast wiring and the coax? Or is my only recourse to add a second thru-deck screw-in connection for the coax? Thanks!