=== Pricing and Left/Right Handle Compatibility ===First of all, the price is for one piece of mirror and I bought a pair. The good thing is the same mirror can be mounted on either the left handle or the right handle as long as it's properly adjusted.=== Assembly Issues ===I was a little concerned about the black plastic inner thread and the metallic outer thread with the metallic nut assembly near the mirror end since I saw people complaining about the durability of the plastic thing. But so far it's ok. But one thing is sure, trying to bend that junction too many times could introduce early worn out. And I definitely don't want to tighten the metallic nut near the mirror end too much in case it strips the black plastic inner thread. Since there is a spring washer between the black plastic and the metallic nut, there is not need to tighten it a lot. As long as that junction does not get loose, it should be ok for normal vibration of the bike. (Mine is a cruiser with no suspensions.)The sheet metal clamp for fixing the mirror to the handle is indeed a bit flimsy but if they are not "flexible enough" it would be difficult to open them before I mount them on the handle. It could be helpful to insert some oil soaked card board layer or rubber sheet to protect the bike handle and to increase the friction.=== Usage ===(1) Never adjust the mirror when riding. It could distract us.(2) Blind spot still exists, but a lot better than nothing, especially for me to see the cars behind me ahead of time, so that I could "prepare for them"...(3) Never look into the mirrors without paying enough attention to the front! Well it happened to me a few times, but it's very dangerous. So glance it and still pay close attention to everything around as if there is no bike mirror.