U.S. Army Sgt. 1st Class Clayton Felton, left, with the Montana Army National Guard's 495th Combat Sustainment Support Battalion, and Staff Sgt. Warren Barrett with the Ohio National Guard's 1486th Transportation Company, complete preventive maintenance checks and services on a mine-resistant, ambush-protected vehicle at Kandahar Airfield in Kandahar province, Afghanistan, April 10, 2013. The noncommissioned officers participated in an event known as Gun Truck Academy, which helped transportation leaders develop standard operating procedures for Soldiers conducting patrols in the Regional Command-South area of operations. (U.S. Army photo by Spc. Rochelle Krueger/Released)