360 ?

I'm going to buy a Helix 9. Is the transducer that come with it all I need or do I have to buy the $1000 360 transducer also?

You'll need the transducer as well as the deployment system, I think. Here is a link with a list of compatible units

The HELIX 9 comes with everything needed to get 2d/DI/SI/GPS chartplotting ...

The 360 is an additional Ethernet accessory (AS GPS HS antenna and Ethernet cable included) that adds the 360 imaging to the above features in the HELIX 9 ...

The HELIX 9 would also need the AS EC QDE adapter cable to connect to the Ethernet cable ...
Humminbird | AS EC QDE

Rickie

Tom,
The Helix 9 comes with what is called the compact SI transducer which will work fine, but for better SI resolution you can upgrade to the HDSI transducer. The information about how to do this should be included with the unit. (If you decide to do the exchange, don't open the transducer mounting hardware)

For the rest....Rickie is spot on as usual.

If you step up to the Helix 10, the HDSI transducer is standard. I don't remember the cost of the upgrade with the Helix 9, but that should be factored in when considering the extra cost for the Helix 10.
If your budget can stretch to the 10, that would be the way to go ...... With these imaging units, Bigger is definitely better.

BobB is referring to an exchange program for new and unused transducers only, and I think the cost is less than $100

Thanks everyone I am just trying to get my head around this new technology. My current sonar is a vexilar. Lol