HELP Yaesu FT-470 & Astron RS-4A

I am just getting back into ham radio after a 7 year absence.
I've got a Yaesu FT-470 and an Astron RS-4A.

Coming out of the Astron is a female cigarrette plug-in.
The male adapter is plugged into that and I've got a small round
female plug at the end of that setup.

I'm missing the piece which will connect that to my Yaesu ft-470.

Can anybody please identify the piece that I'm missing (so I know how to go
looking for it) or let me know if you know where I can buy that piece.

Sorry for my ignorance.... been out of the hobby for too long.

any help sincerely appreciated.

please remove the 'rmve' to respond..... or respond to this group
Thanks.............and 73's

[EMAIL PROTECTED]