2" OD worked for me. Mounting bracket to the bumper structure behind and above and purchased a prebuilt switch / relay wiring harness; however, I sourced another oe hazard light switch and installed it in the blank at the shifter bezel. I can probably get the links to all if the ebay history hasn't expired yet but you many not like the fogs being they have "angel eye" surround that I have wired to turn on with my parking lights.
Email me for pics.
Tractionless@comcast.net as I'm not subbing.
BTW that's much more help than I got when finding a member who had them. I was told, "go look around ebay." Thanks bud!