A support technician from the 27th Aircraft Maintenance Unit engraves a wrench as a means of keeping track of the tool at Langley Air Force Base, Va., Feb. 15, 2013. The technicians at the 27th AMU are accountable for more than $10 million worth of tools and assets, so marking and maintaining all equipment is a required practice. (U.S. Air Force photo by Staff Sgt. Jeff Nevison/Released)