Cabin Pressurization Compressor Indicator, P-3 Orion US Navy US Gauge SRD-9B
This is for a Compressor Pressure Indicator used in the US Navy's Lockheed P-3 Orion Anti-submarine aircraft. Two indicators appeared on the panel at the Flight Station, each monitoring the inlet (I pointer) and discharge (D pointer) pressure of each compressor. See photos of the diagram and descriptive text from the P-3 Flight Manual. Measures 2.in diameter and ~3in deep.