Hydraulics is a form of propulsion technique in which forces and movements are transmitted through liquids. Often, oil is used as liquid. The fluid used flows through the conduits containing the hydraulic system in question. The fluid is pressurized by means of a hydraulic pump. When the oil is pressurized by the pump, the pressure generated will cause the hydraulic cylinder to move. This enables the hydraulic system to perform work. Then, by means of hydraulic valves, the pressure in the double acting cylinder is converted to the opposite direction. As a result, the cylinder is shifted back to its base position.