My good luck charm is hooked to my key chain and I often take it with me when I am running as well as when I'm in the car. I actually carried it with me through Colorado on the TransRockies course! It was hooked inside a pocket in my pack. Indeed, on Stage 5 when I got my asthma inhaler out for a friend who was having trouble breathing because of all of the dust, I ran the last mile with that pocket unzipped and open, and did not lose it (whew).
The significance of the talisman is this: it features St. Christopher, who is the patron saint of travelers and children. Well, I'm not a child, but I fell like a kid at heart. And I travel often, and on foot, so a little looking after by good St. Christopher is much appreciated by myself. On the back of the medallion, it says, "God protects you" in German. You can read more about the saint here.
If you are traveling in Europe, and especially in southern Germany, you will notice that the taxi drivers and even some of the buses, and many of the private citizens have St. Christopher medallions mounted on the dashboard of their vehicles or carry a St. Christopher key chain. Someone asked me if this was strange, because he thought Germany was more of a Protestant country, when in fact southern Germany is predominantly Catholic.