Its a B744v as Hookup said. https://www.airmar.com/Catalog/Marine/Traditional-Frequency/Thru-hull/B744V
It is an old school "traditional" 600w CW 50/200khz. With an adapter, it will work with any brand new sonar. However, it will not support the CHIRP feature of new sonars.
It uses a 2" hole...