I picked up a used HDS 9 Gen 3 and an HDI Skimmer from a guy that was selling all his Lowrance units. I run Humminbirds but wanted to try a Lowrance on the bow to see if there was a difference in the 2D returns. I have not had time to install the unit yet but I have noticed a few posts stating you need a structure scan box with certain transducers. My questions is - will the Skimmer plug straight to the HDS or do I need something additional for this setup? This is just kind of an experiment as I am not unhappy with my HB units but wanted to see if there was a difference so I am not sure I want to put more money into this experiment. Any help would be appreciated, thank you,

You will be able to get 2D sonar and down scan with the HDI transducer. It's plug and play. To get side scan you will need a LSS or a Total scan transducer.

Perfect, thank you, that is all I was looking for out of it.

You do not need a box for the HDI. The HDI should have the standard Blue connector that plugs into the blue sonar connector of the HDS Gen3. If you are going to install the HDI on your trolling motor, you will need a trolling motor mount kit ($20) and most of the time they are in stock at Bass Pro (see them in stock at the Grapevine store all the time). If the HDI and Gen-3 unit were connecting and working together from previous owner, it should be plug & play. If you have any issues, don't hesitate to call me - 817-319-1194.

Thanks Rob. The other person was selling multiple units and piecing everything out. I originally thought this setup would work then I started question myself. I will definitely reach out if I have any issues when I actually get around to installing the unit. Thanks again