United States Marine Critical Skills Operators with 1st Marine Special Operations Battalion, Marine Corps Forces, Special Operations Command, wait aboard a CASA 212 aircraft in the process of gaining altitude to conduct a double-bag static line (DBSL) jump, during a DBSL parachute training course, Aug 26, 2014, in rural Arizona. 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)