If you want to transport bikes in a small car or you need to transport your bikes with demounted rear wheels for other reasons, like much extra luggage.
The Bikeinside chainring protector protects the car interior against dirt and the rear derailleur from damage. The bikes stand on the chainring in chainring protector.
The chainring protector can also be used to protect the bikes if you want to transport many bikes so they stand very close in the vehicle.