EIELSON AIR FORCE BASE, Alaska --   U.S. Air Force Senior Airman Timothy Carlson, a 354th Maintenance Squadron non-destructive inspection (NDI) journeyman, guides Staff Sgt. Zachary Chambers, a 354th MXS NDI craftsman, as he aligns an x-ray tubehead on Eielson Air Force Base, Alaska, Dec. 9, 2020. NDI specialists utilize x-rays, ultrasound, and other means to find the smallest imperfections and take corrective measures. (U.S. Air Force photo by Airman 1st Class Jose Miguel T. Tamondong)