Asco offers the worldÕs largest selection of 2-way, 3-way and 4-way solenoid valves, designed to handle the most demanding fluid control applications. 2-Way Solenoid Valves have one inlet and one outlet, and are used to permit and shut off fluid flow. 3-Way Solenoid Valves have three pipe connections and two orifices. When one orifice is open, the other is closed and vice versa. 3-way solenoid valves are commonly used to alternately apply pressure to and exhaust pressure from a valve actuator or a single acting cylinder. 4-Way Solenoid Valves have four or five pipe connections, commonly called ports. One pressure inlet, two cylinder ports providing pressure to double acting cylinder or actuator, and one or two outlets to exhaust pressure from the cylinders.