Has anyone tried this ?

Schwinn Handlebar Mirror

I find that it vibrates a lot and gets constantly out of alignment making it thoroughly useless.
The mechanism to lock the mirror in position is a plastic threaded collar and I am afraid to strip the threads by overtightening.

I have another mirror - no name - and it works fine when mounted on a bar end but on a bike without bar end the arm is too short to be effective as rearview mirror. Is there any mirror available with about 12" long arm that can be mounted on a handlebar on the right side of the left hand brake lever clamp?

I also find that convex mirrors are quite useless as when the car in the rear is visible, it is too close.

I do have a Blackburn helmet mirror but have not yet managed to find a good position to fix it to my helmet.