Review on EEEkit Bike Mirror Set - 2pcs HD Safety Rearview Mirrors with Scratch Resistant Convex Lens for Universal Adjustable Handlebars on Road/Mountain/Kids/Adult Bikes by Rick Pickering

The expandable mounting ring was MUCH large for the bike handlebars I needed to fit it into (although the handlebars appeared to be a fairly standard size). It took several attempts at grinding and the use of wire cutters to reduce the size of the ring enough to fit. But once installed, they're fine. Adjustment is good as the attachment end may need to be rotated a bit to find the orientation that allows the mirror to rotate best for your preferred viewing angle. I'm glad they are out there and working now, but if I had known how difficult it would be to set up I would have bought something else.