Take a Look mirror

[featuretile]

I bought one of these when I went from a hybrid with a side mirror to a road bike where I could not mount a side mirror. It did not work for me on a helmet as the helmet can be in slightly different positions and there is some vibration. I put it on the left side of my sun glasses. If you look with your left eye and can see the very top of your shoulder when you lean forward (as you would be positioned on your bike) and the very edge of your left ear, the mirror will be in the right position to see traffic and whoever is riding behind you.

I also discovered a really unusual thing. My left eye is very near sighted and I did not know if I would see anything behind me. But since the mirror is so close to my head, I can see what's behind me very clearly. Now I feel like I riding blind if I don't have my mirror.

[cosc]

I also found vibration much less on my sunglasses than helmet.
I would go with the larger mirror.
I've seen some mirrors adjusted with the lengthwise vertical, but I've always had mine lengthwise horizontal. Someday I might try it the other way but I've been satisfied. I think mirrors can be a lifesaver especially since I ride on a road with lots of traffic. I do like to know when I'm king of the road or not.
Women here have given you great advice, just give your brain a chance to adapt.

[Melalvai]

It took me about 2 hours of riding to adapt. But for a couple weeks I still squinted one eye to see into it (to get rid of the overlapping images).

$8 sounds reasonable. I think mine cost $14 plus s&h.

I only use the mirror to ascertain that there IS a car behind me. If I think there is NOT a car, I confirm it by scanning. I think there may be a blind spot with a mirror. It's also really useful for keeping tabs on riders behind me, if I'm riding with my daughter or someone.