I drive a school bus and really get used to having rearward visibility....would you trust that many monsters in close proximity to you????
Honestly, it's only used for glancing on activity behind you....with road vibrations and such there's not a lot of detail to be gained.
I purchased a rear view mirror from the automotive section of a local chain store (sorry it's a Canadian thing.......Canadian Tire) It's about 12" wide, and slightly convex to give a wider view. I mounted it by attaching to my sun visor...........the visor is useless for being a visor....I have the visor in the down position and attached the mirror to that. It gives me enough information of what may be happening behind....but it vibrates a fair bit too.
Clip-On Wide-Angle Mirror | Canadian Tire