Abstract: A nine position air pressure regulator includes a main regulator body member having an unregulated first pressure cavity, a regulated second pressure cavity and a valve seat between the cavities. A diaphragm is in sealing relationship to the second cavity, and the first end of a pressure regulation spring presses against the diaphragm to tend to force it into the second cavity. The spring operates inside of a cylinder, and a yoke is located at the second end of the spring away from the diaphragm. A rotor ring is rotatably mounted with respect to the main body member and threadably mounts a plurality of pairs of cap screw stops. The stops of each pair of screw stops are spaced 180.degree. apart from each other around the rotor and are adjusted to terminate at the same distance from the rotor bottom. By rotating the rotor ring, any desired pair of screw stops can be vertically aligned under the outer ends of the yoke.