We used to carry the Mirrcyle mirrors and the issue some riders have is that they are quite fragile. Overtighten the screws or ding it against a wall, bike rack etc... they typically crack. We would typically have about 20-30 issues per year with these.
We then started carrying the B&M Cyclestar mirrors and they are far superior in terms of quality. While they cost about 2x as much they will give riders years of trouble-free service, some are foldable and are simply the best in the market in my opinion. Since carrying these mirrors we have had "0" complaints or issues. Customers are happier with these.
https://scooteretti.com/collections/bicycle-mirrors
Will