What is a tow bar ?

The tow bar is affixed to the tow vehicle.  This provides the link between the vehicle and the caravan or camper trailer.  There are lightweight and heavy duty tow bars.  The tow bar should clearly identify its maximum towing weight rating and its maximum ball mass.

What is the Australian Standard for a towball ?

The Australian Standard is 50 mm and the rating must be stamped on the ball.  Always check this to verify the towing weight capacity of the ball.  The rate can be between 750 kg and 3,500 kg.