Oil-68 Hydraulic Oil are non-compressible fluids that are used in all types of hydraulic machinery including cranes, diggers, drill floor power units, hydraulic ring mains etc. They can be synthetic or mineral based. They can be used as a sealant, coolant or lubricant and are also used in the transfer of power in machinery. Hydraulic oil is the most important material in hydraulic machinery. The selection of the hydraulic oil varies according to the hydraulic system and application. Viscosity is the major factor in selecting a hydraulic fluid as it increases the performance of the machinery.