A trooper assigned to 2nd Squadron, 2nd Cavalry Regiment conducts preventive maintenance checks and services on two of his unit's M240B machine guns in Mihail Kogalniceanu, Romania, during his unit's ongoing support of Operation Atlantic Resolve, March 22, 2015. During OAR, troopers will be living and training alongside their NATO allies and European neighbors, helping to maintain the relationships and trust that are essential for ensuring regional security. (U.S. Army photo by Sgt. William A. Tanner/Released)