2 head units?

Hello all! I have a project on a boat, a yaht more like it, right now it has 2 headunits that talk to each other, one inside the cabin. He wants me to redo everything in this boat, but the wants to keep it where he can control the other headunit from inside the cabin and viseversa, Im not sure how this work right now, but i was looking for something on this, and i have googled the heck out of it, can someone shed some light one this for me please?

Many marine head units have remote displays that can control the HU from another location such as inside the cabin. Check out sites such as www.clarion.com for more details.

I have seen these, but right now it is a single din headunit, the remote display would work if it was not a single din location, it is in the middle of the dash so i cant just put a new piece of plastic there, is there anything else?

I'm not aware of any 2 aftermarket DIN sized units that would control each other. Quoted from your previous post... "the remote display would work if it was not a single din location" The remote units are not DIN sized so I'm not sure why that wouldn't work.