4820-01-052-9253 (381-1040P8)
NSN 4820-01-052-9253 (NIIN 01-052-9253) is a safety relief valve in Federal Supply Class 4820, Valves, Nonpowered — a valve designed to automatically release excessive pressures. Manufacturer part number 381-1040P8 (Raytheon Company, CAGE 3B150); also referenced as 559A2M4 (Circor Aerospace, Inc.).
Key specs: 150 psi maximum single response operating pressure; full characteristics table below. NIIN assigned December 1977; DEMIL A (none required); unit of issue EA (each), $266.40 gov standard price; export Schedule B 8481.40.0000.