I much prefer the glasses mounted Take-A-Look mirror (REI, etc.) from Bike Peddler. I have tri-focals and have no problem with that. Comes in two sizes....I use the smaller and find it more than enough. Easy to adjust while riding. Helmet mirrors were too vulnerable to getting knocked off and, for me, required more head tilting and were less easily adjusted. My one handlebar mirror vibrated too much
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