Staff Sgt. Juan Mercado Guzman calibrates a gas port erosion tool Aug. 16 at Aviano Air Base, Italy. Mercado Guzman works in the 31st Maintenance Squadron precision measurement laboratory as a technical measurement diagnostics equipment technician. The PMEL office members calibrate more than 6,000 pressure measuring devices for seven different bases throughout Europe. (U.S. Air Force photo/Airman LaVel Sterling)