On the screen size. If your face is close enough to the 7 it will be big enough to work SI. The bigger screens do come into good play when you are having more than one function going on the same screen however.

I used a Helix 5 side imaging on my pond boat to deadly effectiveness. The 5 actually has higher resolution than the 7 and the 9. Extremely crisp image on the 5 just smaller. I went to the Helix 7 on my pond boat to get the Ethernet feature so I could use my 360 transducer on it. The 5 does not have Ethernet. Otherwise I would still be using the 5. But the 7 is nice. I would not want the 9. It has the poorest resolution of all these units even though it's screen is bigger. I would jump up to the 10 instead. Much better resolution than 9. I used the transducer trade-in service to get the HD transducer for my 7. It helps. It helped on the 5 too.

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