You can either have a window mount or the option I choose, Super Strong 3M double sided tape... I attached the holder with the tape to my magnet so I would not mess up my truck paint. I have gone like 60 mph and it hasn't moved at all. Plus the other night, we had 60 mph wind gusts and it didn't move. I think the magnet will fall off before the holder. Also, I can still put down the tailgate and the magnet or the holder won't fall off. Very happy with how it turned out!