The point of direction for the hitch on the truck. All office trailers and modulars use a 2 5/16" hitch ball.
The steel ball bolted through the ball mount adapter or hole in the tow vehicleâ€(tm)s rear bumper. The coupler on the trailer goes over the hitch ball.
The ball-shaped attachment to a hitch onto which a trailer coupler is attached. We sell Hitch balls here.