Directional control valves in control devices control the direction of flow in the system as well as stopping it and thus determining the direction of movement of the actuators, whether cylinders or hydraulic motors. Directional valves are named according to the number of service ports in the valve and the number of connection positions, as they are named by two numbers, either 3/4 or 2/4, as directional valves work to control the pressure in the hydraulic circuit or equipment parts and are divided into safety valves, pressure relief valves, sequence valves, brake valves, parallel conterbalance valves, and pressure unloading valves.