Here at army surplus world we carry U.S. Air Force Challenge Coins. The U.S. Air Force Challenge Coin is two sided, made with premium metal and, has a diamond cut edge. The U.S. Air Force Retired Challenge Coin Challenge Coin is approximately 1-5/8 in diameter. The U.S. Air Force Retired Challenge Coin challenge coins have been upheld as treasured symbols of an unbreakable bond. Order your U.S. Air Force Retired Challenge Coin for your own collection or as a gift from Army Surplus World today!