36th Maintenance Squadron Precision Measurement Equipment Laboratory
Elijah Bacchus, 36th Maintenance Squadron Precision Measurement Equipment Laboratory technician, measures the flatness of a calibrated surface using and optical flat and monochromatic light June 19, 2015, at Andersen Air Force Base, Guam. When an optical flat's surface is placed in contact with a surface to be tested, bands form when viewed with monochromatic light, which gives a visual representation of the flatness of the surface being tested. (U.S. Air Force photo by Airman 1st Class Arielle Vasquez/Released)