This is called a visor clip, it's just to show the concept. Using a small machine screw, attach the visor clip to the back of the holder, use a small washer to allow the visor clip to stand just proud of the holder. The visor clip would allow attaching to the visor, providing the ability for the visor clip to rotate on the machine screw, with some friction so it will stay in place, This would kill two birds with one stone; if the clip is rotated so that the body of the clip is over the hinging area of the cover it will prevent accidental opening and loss of the scent packet, rotated 180°, it would allow the cover to be opened for replacement of the scent packet. ta da!