4820-00-225-0977 (128SCH131-1)
NSN 4820-00-225-0977 (NIIN 00-225-0977) is a safety relief valve in Federal Supply Class 4820, Valves, Nonpowered — a valve designed to automatically release excessive pressures. Manufacturer part number 128SCH131-1 (Northrop Grumman Systems Corporation, CAGE 26512); also referenced as HP545100 (Tactair Fluid Controls Inc).
Key specs: pressure tight outlet side; 80 psi maximum single response operating pressure; full characteristics table below. NIIN assigned January 1961; DEMIL A (none required); unit of issue EA (each), $5,176.55 gov standard price; export Schedule B 8481.40.0000; ships at 0.63 lb / 0.0197 cu ft. Related NSN 4820-00-083-1250.