The PVD-0B-12P piston pump is designed to work with specific types of hydraulic fluids. The recommended hydraulic fluid should have appropriate viscosity, anti-wear, and anti-oxidation properties. The suitable viscosity range of the hydraulic fluid is generally between 10 - 400 cSt (centistokes) at the operating temperature range of the pump, which is typically from -20°C to +80°C (-4°F to 176°F). It is important to use the correct type of fluid to ensure the pump's proper operation and longevity.