These types of solenoid valves are like everyday five/two-way valves but While using the addition of the center posture as its standard state. They have two solenoids and two spring return mechanisms to allow the actuator to return. This put up discusses the position of various types of linear actuators https://eduardohpuyd.bloguetechno.com/Facts-About-Pneumatic-actuator-solenoid-valve-Revealed-50017101