Sgt. Donald Armstrong explains a biometric scanning system to Deputy Secretary Carter U.S. Army Sgt. Donald Armstrong explains a biometric scanning system to Deputy Secretary of Defense Ashton M. Carter during a counter Improvised Explosive Device training exercise, on Fort Campbell, Ky., on June 20, 2012. Armstrong is assigned to the 101st Airborne Division. SHARE: Download: Full Size (0.06 MB) Credit: VIRIN: 258794-Q-JGG14-869.jpg Photo Gallery