Challenge coins originated during World War I. They were issued to battalions as symbols of camaraderie and unity. Later, they were used as a way of verifying membership in a club group, or military unit. Challenge coins are now commonly given away at military and patriotic events and DOD meetings as a token of appreciation or as a promotional product. Pricing includes up to 4 colors on both sides of the 2" coin.Nickel finish and flat edge border are standard, for gold or antiqued finish and additional edge options call for pricing and details.