These do NOT work with last year's (or older) Knowledge Turbo Fan OTG goggles. You have to make sure you have the newer version with a plastic insert inside the nose of the goggles. Smith doesn't mention this on their website, but I just blew $20 on 2-day shipping to learn it. Thanks a lot Smith! Backcountry, meanwhile, rocks. I've never had an easier experience with a return... Check Status, Return, Print UPS label, and I'm handing the box the the UPS man. Nice.
The quality of the lens insert looks great, too bad I can't use it.