I used them for two years until I fell off my sled and they both exited my helmet. I agree with leaddog. I also think they look kinda cool. The only thing I have to say on the negative side is since they're so close to your eyes, it takes a bit longer to adjust your eyes to view the object. Also, sometimes it takes a bit of movement from your head to get the object your looking for in the mirror. Often I'd have them adjusted so when looking in the right hand mirror, I'd have to slant my head a bit and to the right to see who was behind me. I'll be getting two more this year.
Jon