[CA] Axiom transducer selection

I would like to purchase a down vision or real vision transducer for my Axiom MFD.
I would like a thru hull transducer and if possible the dimension of the shaft of the new transducers that will work with the Axiom. My Axiom is an Axiom 9 with real vision.
My boat is a 1983 Tiara 31 open.

Thanks,
Joe
jbacile@gmail.com