THe best part of those trucks is that the letters are easy to peel off and rearrange. I have personally altered about 15 of them. I am always on the lookout for someone elses similar works.

I had a football coach that had something like this on a lanyard. Was supposed to be for when someone was knocked unconscious, the device could be screwed in between the teeth in order for a trainer or physician to keep a player from swallowing their tongue. That's what I was told anyway.