Senior Airman Matthew Krzywiecki, 379th Expeditionary Aircraft Maintenance Squadron, 746th Expeditionary Aircraft Maintenance Unit, puts on his personal protective equipment prior to working with liquid oxygen September 9, 2015 at Al Udeid Air Base, Qatar. The 746th AMU cryogenics airmen work with liquid nitrogen and liquid oxygen that is recharged into aircraft, providing aircrews with pure oxygen at altitude during missions in support of Operation Inherent Resolve. Krzywiecki is a deployed member from the 911th Airlift Wing, Pittsburgh International Airport Air Reserve Station, Pa. U.S. Air Force photo/Staff Sgt. Alexandre Montes)