Pull the stock mirror and pull the front cover off. There are some metal rings that you need to cut with a dremel. This is what is non-reversible. Once you get that off, you'll be left with the ball mount. I used the mount kit from Wolfbox to attach to the ball mount. I did have to use a rubber strip to take up a little slack, but its been really solid.
Altenatively, you can go here and choose 3b (make sure you research the exact part number).
