Suggestions for adjustment: one side can see behind him, the other side can see himself and the area behind the three quarters.
After confirming, lock the nut again.
But anyway, when changing lanes, we must pay attention to the "two shoulders" inspection.
Some models have reached a certain speed, and the rearview mirror is blurred due to excessive vibration. At this time, you can try to add a thick rubber washer or a professional shock absorption module to the rearview mirror installation position to reduce the vibration Impact.