Mobil Aero™ HF Series aviation hydraulic fluids are designed to meet the demanding requirements of commercial and military aircraft applications. These high quality formulations have a long history of excellent performance and provide long, trouble-free service over a wide range of operating conditions. Mobil Aero™ HFA and Mobil Aero™ HF aviation hydraulic fluids are formulated for aircraft systems where use of hydrocarbon-based hydraulic fluids is required. They are low-viscosity products, high VI (viscosity index) fluids with excellent low-temperature properties, good antiwear performance and good chemical stability. Mobil Aero HFA and HF hydraulic fluids are composed of mineral base oil stock and contain shear-stable VI improvers.