Lt. Col. Kong Rithy, Royal Cambodian Air Force weapons and aerodrome specialist, looks at a refractometer March 17, 2016, at Andersen Air Force Base, Guam. A refractometer is a tool used to determine percentages of fuel additives. Pacific Agility is a Pacific Air Forces-led engagement focusing on a series of logistics subject-matter expert exchanges designed to increase partner capabilities, military relations and regional stability for the Indo-Asia-Pacific region. (U.S. Air Force photo by Airman 1st Class Arielle Vasquez/Released)