U.S. Air Force Staff Sgt. Aryol Alvarado-Espinoza, 633rd Security Forces Squadron installation entry controller from Joint Base Langley-Eustis, Virginia, conducts night operation entry control procedures during a field training exercise at Marine Corps Base Quantico, Virginia, July 31, 2019. During the FTX, members of the 633rd SFS practiced a multitude of techniques ranging from patrolling, reacting to indirect fire and entry control procedures. (U.S. Air Force photo by Airman 1st Class Marcus M. Bullock)