4820-01-063-0053 (SS845-2181251ASSY)
NSN 4820-01-063-0053 (NIIN 01-063-0053) is a check valve in Federal Supply Class 4820, Valves, Nonpowered — a valve permitting flow in one direction only. Manufacturer part number SS845-2181251ASSY; also referenced as SS845-2181251, SS845-2181251AS, SS845-2181251ASSY RD 5IN (Naval Sea Systems Command); 2620-927X9 (Electric Boat Corporation).
Key specs: 700 psi maximum single response operating pressure; full characteristics table below. NIIN assigned July 1978; DEMIL A (none required); unit of issue EA (each), $3,313.59 gov standard price.