U.S. Air Force Staff Sgt. Mark Cravens, 17th Security Forces Squadron kennel master, applies a muzzle to military K-9 Hugo as a part of his retirement tests on Goodfellow Air Force Base, Texas, April 22, 2020. The application of the muzzle was one aspect of the tests administered to a military K-9 to show that they are ready for retirement. (U.S. Air Force photo by Senior Airman Seraiah Wolf)