Slip on towing extension mirrors go over Ford OEM mirrors. Used on a 1999 F150, but fits other years as well...do your research online for CIPA 11802 and 11802. (R&L)
You pay the postage, I'll give you the mirrors. Includes the mounting wedges, 2 pair, for two types of OEM mirrors.
Here's one link to the mirrors.
Unless your vehicle is a 1999 F-150 you'll need to do the research to see if these will work for you. I hope they do.