Master Sgt. Tim Williams, a career maintainer and now a member of the Office of the Warrior Advocate, walks his service dog, Peter, through their final test for certification at the Omaha Gun Club, Dec. 10, 2019, Omaha, Neb. Peter is a rescue dog that has been adopted by Tim to help with his Invisible Wounds. (U.S. Air Force photo by Josh Plueger)