Bryan G.wrote a review of Oakley Flak Jacket XLJ Replacement Lens on October 14, 2012
Familiarity: I've put it through the wringer
I have the Black Iridium XLJ polarized replacement lenses. They fit perfectly in my matte black frames, so I don't know what the guy who said they "rattle around"is talking about. It took me about 2 minutes to get the hang of popping the lenses out and back in to swap them around. It's really not hard. The iridium coating makes the lenses mirrored from the outside. The polarization is good and these are pretty dark, but very clear.
Plus they were 20% off and free 2-day shipping. So yeah, I'd recommend.