Castrol Aero™ HF 585B is a red mineral oil based low viscosity hydraulic fluid which is intended for use in hydraulic systems where rapid system response is required, particularly at low temperatures. Castrol Aero HF 585B is ideally suited to accumulator driven emergency control systems. Castrol Aero HF 585B is produced from low viscosity highly refined mineral basestock, shear stable viscosity index improver, antioxidants, corrosion inhibitors and anti-wear additives.