Instruct: Classify a given review as either positive or negative.
Query: Never ride without it

Funny enough, I just bought this as an add-on for another order to qualify for free shipping. Best little accident ever. This mirror has gone beyond expectations (which after my experience with handlebar mirrors, was not good). It's great for keeping an eye on traffic behind you when preparing to merge left. No more having to do 3 or 4 shoulder checks, just casual glances in your mirror. Mirror is very adjustable (arm and mirror itself swivel as needed) and seems to stay where you put it. Vibration has very little effect on all but the bumpiest roads.Depending on your glasses, the mirror can be somewhat hard to figure out how to mount, but generally once you find out how you need to do it, it's no problem. The 'arms' have rubber tubes you can slide up and down to help grip the arms of your glasses properly.Also a big fan of the plastic. In case of a crash, it will break away rather than threaten your face with a solid metal piece.