A glow-in-the-dark 2" PVC patch. A revamp of our original Labyrinth coin that fits the wallet a bit better and can be docked in any number of shapes.
There's a story that before 9/11 a case officer in Afghanistan got orders to shut down shop. Before leaving, they cut a coin in half, gave one half to the village elder, and kept the other so the village would know any returning officer was legitimate. In the days after 9/11, a lone officer went back to that northern village to rally a force against the Taliban. When the elder, long dead by then, was gone, the village still brought forward the other half of the coin. A lone traveler in a dangerous land was instantly a member of a tribe that would shed blood beside them. It's just a story, of course. Something like that would never be allowed to be told if it were true.