The valves enable flow direction control of fluid in a hydraulic circuit and both control of the direction of movement or (shutting off) stopping of their appliances. In addition to solenoid operated valves, valves are also operated mechanically by lever or cam, hydraulically or pneumatically. Pilot operated directional control valves are designed to achieve a high flow rate of up to 600 l / min. Poppet type valves are known for their extremely low internal volume loss.