I think the HDI has a nine pin connector on it and not the seven pin connector like the regular 2D ducers.
If your other one is a nine pin, I can use it. You won’t even need to mess with shipping.It does have the blue locking collar, but it’s currently in transit to the OP, I hope it’s what he needs!
The second ducer(trolling motor mount?) is available if someone can use it, and I can verify pin count if needed, just cover the cost of the f shipping and it’s yours.
After doing a little reading, I think that should work. In Lowrance speak, it’s a 7 pin connector because it can have up to 7 pins, even though that one only has 5. See the extra blank spots?