The 2546 pneumatic control heads were designed for controllable pitch (CP) propeller and engine speed functions. The longer handle will actuate 2 pressure regulating valves, providing "0" pressure for "0" pitch, and in case of failure, the CP actuator will return to "0" pitch position.
The 2546 is available with labels, and have a maximum supply pressure of 150 PSI (10.3 BAR) and 1/8" NPT.