Best depth transducer for eS127?

We just bought new Raymarine instrument packages (eS127, charts, EV400 autopilot, AIS), and hoped we'd be able to re-use our Raymarine inside-the-hull transducer, but it only has 4 pins (from a DSM250). What is the correct transducer to replace it? We are sailors - nothing fancy, just depth. It looks like it should be a P79? Are there any other alternatives?

Thanks in advance.

Bill