A "convex spotter" refers to a person who helps others by identifying potential dangers or problems, like a spotter assisting someone driving a vehicle. Full definition
Includes integrated turn signal indicators consisting of 51 square inch flat mirror surface positioned over a 24.5 square inch convex mirror surface with a common head and lower convex spotter glass (convex glass is not heated and not power - adjustable) and addition of Auxiliary cargo lamp for backing up (helps to see trailer when backing up with a trailer) and amber auxiliary clearance lamp (tveauto.com)
Fortunately, the Ford comes with large convex spotter mirrors, helping us judge the size of gaps in traffic. (automobilemag.com)
* Integrated Spotter Mirrors — The traditional side - view mirrors are designed with a secondary convex spotter mirror in the top outer corner, which provides a view of the driver's blind spot. (thetorquereport.com)