I used the Johnny Ray JR400HLP-M Swivel Mount and Adapter Plate for my Lowrance Elite-4 Gold unit. It was a perfect fit and now provides me the flexibility to swivel the unit so anyone in the boat can see the screens when drifting. Having the swivel base also allows me to rotate the screen out of occasional sun glare situations. Just push the button and you can detach the adapter plate from the base in a few seconds. You do have to drill the holes in the mounting plate that Johnny Ray supplies to mount the Lowrance Elite -4 base, but it is very easy and takes about (5) minutes.
Made in USA which is a huge plus in my book.