Hello together! Can anyone tell me if there is a difference between the box and the box (316 CDI, W903) in the photos of the trailer coupling? So the AHK of a box also fits the box/bus? I have tried both the search here and also various search engines of the Internet, but was unfortunately not found. Except that I am even more confused now, since there are obviously different photos for the boxes alone (pictures at various dealer page) n). I thank you already in advance!