Any Marines out there with challenge coins. If so I have a couple of questions. 1 what are they(I have seen them and know the physical shape) but what do they stand for. Second, do you have them displayed in a shadow box or something of alike. Reason I ask my uncle has about 30 or so, and I would like to make something for him to display them. However I am not where he is and do not have access to them. So I will have to do some research and take a guess how to build a display for him. Any help appreciated.