I was intrigued to read this when browsing the Q5 accessory brochure.
Approximately 12 litre bag in Audi design with Peltier technology powered by the 12V socket. Cooling to
a maximum of 20̊C below ambient temperature. Must be used with a steel tow ball
Any idea why it "Must be used with a steel tow ball", or is this an error? Can't see why it would need it.