United States Marine Critical Skills Operators with 1st Marine Special Operations Battalion, Marine Corps Forces, Special Operations Command, wait for their double-bag static line (DBSL) parachute training to commence, at a secluded Arizona flightline, Aug 26, 2014. The DBSL course is an introduction to the High Altitude, High Opening (HAHO) insertion method utilized by Special Operations Forces. (U.S. Marine Corps Photo by Lance Cpl. Steven M. Fox/Released)