A U.S. Marine Critical Skills Operator with 1st Marine Special Operations Battalion, Marine Corps Forces, Special Operations Command, guides himself to a dropzone in the Arizona desert, during a double-bag static line (DBSL) parachute training course , Aug 26, 2014. The DBSL course was 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)