Having tried many brands of mirror over the years and finding many too wobbly to give a clear view, I have had most success with the B&M 901/2 model, though they now do a larger diameter 903/2 and many many variants of arm length plus massive e-bike left mirrors too.
As well as a bar end fittings there is a strap type accessory to which the mirror can be fitted if you have bar end shifters.
I think the US website run by Peter White illustrates them well....
http://www.peterwhitecycles.com/mirrors.php.
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