Senior Airman Michael Daniel, 28th Maintenance Squadron hydraulics journeyman, installs an auxiliary power unit piston in an APU in the 28th MXS Hydraulics Shop at Ellsworth Air Force Base, S.D., Jan. 19, 2012. Ellsworth maintainers build and maintain various hydraulic components that keep Ellsworth’s B-1B fleet mission ready. (U.S. Air Force Photo by Airman 1st Class Kate Thornton/Released)