US Air Force (USAF) AIRMAN First Class (A1C) Arturo Castillo, a Security Forces Journeyman with the 27th Security Forces Squadron (SFS), Cannon Air Force Base (AFB), New Mexico (NM), uses a range-finder to determine his effective line of fire while preparing his defensive position during Exercise Eagle Flag at Naval Air Engineering Station (NAES) Lakehurst, New Jersey (NJ)