Five-port, two-position solenoid valve directing compressed air to a WAM pneumatic valve actuator. Monostable versions spring-return the actuator to a defined fail-safe position on loss of signal; bistable versions hold the last commanded position, which is what you want where a power blip should not slam a valve shut mid-discharge. Takes the BOB coil range in 24V, 48V, 110V and 220V AC or DC.