Bolt Lube Multi-Viscosity Hydraulic Oil's blend of high-viscosity-index base oils and performance additives provides all-season protection and reliable operation in all types of hydraulic systems.Hydraulic Oil has many roles in the smooth operation of a well-balanced and designed system. These roles range from a heat transfer medium, power transfer medium and a lubrication medium. The chemical makeup of a hydraulic fluid can take many forms when selecting it for specific applications. It can range from full synthetic (to handle drastic temperature and pressure swings and reduce the rate of oxidation) to water-based fluids used in applications where there is a risk of fire and are desired for their high water content. Available in Fully Synthetic (Titanium) , Semi-synthetic (Gold) and Mineral based (Silver).