What is "tourers"

Usage examples of "tourers".

A long procession of open four-door Mercedes tourers was approaching down the Via Triumphalis, chromework gleaming like mirrors, passing between the closed ranks of fifty thousand brown-uniformed storm troopers who lined both sides of the way, holding back a dense throng of humanity, ten and twenty deep, who roared with adulation as the leading vehicle passed them and threw their right arms high in the Nazi salute.