As was mentioned in another review, it is has a bit complicated to you attached the adapter for the first time. Until you get out is, how it works, it took a little bit. For me it was the "trick" that you have to turn the plug on the trailer first, then the adapter off and then turn back. Here, the adapter draws then fixed to the other end off and sits extremely stable. Perfect! But if you first as usual tried to put him only "plan", then it does not work