The difference between the HELIX 10 SI GPS and the HELIX 9 SI GPS covers quite a bit more than just the 1" difference in the display diagonal. The HELIX 10 also comes with the HD transducer, and it's 800 kHz capable right out of the box. Evidently, there's much more to say about this unit, so let's start with its sonar capabilities. First of all, this unit uses three types … [Read more...] about Humminbird Fish Finder HELIX 10 SI GPS Review