Alpha Series Pilot-Operated Pneumatic Valve, 4-way 2-position, Spring Return, 1/4 NPT (Side) Ports, 50 Flow Rating

Operating range goes from vacuum all the way up to 150 PSI, so it covers a pretty wide spread of working conditions. Minimum pilot pressure sits at 50 PSI, so as long as your signal line is at or above that, the valve will actuate properly. The spring return means one side is always mechanically driven back, so you're not dependent on a second pilot signal to reset it.

Function-wise, it is a 4-way, 2-position directional valve with a spring return spool action. That setup is commonly used to shift air flow for an actuator, then return to its normal position when the pilot signal is removed.