The valves covered by this specification are intended for use in aircraft type II hydraulic systems conforming to SAE-AS5440. The complete requirements for these valves consist of SAE-AS8775 which covers general requirements common to all aircraft hydraulic components and this specification which includes additional requirements specifically applicable to shuttle valves. These valves are designed for emergency hydraulic systems for military aircraft only and not available for commercial aircraft. The type I valve is intended to mount directly in the aircraft and the type II valve has threaded ports intended to be mounted in the hydraulic line.