US Air Force Presented by the TMO Sam Ames For Outstanding Service Challenge CoinMeasures Approximately: 1.50 InchesNo Special EdgingFront: Presented by the TMO For Outstanding Service, TMO, Sam AmesBack: Integrity First, Service Before Self and Excellence in All We DoChallenge Coins are generally created for the Military and are prized by the service members that receive them. Perfect for Collectors of Militaria.