5310-01-668-1663 (01D2957H09)
NSN 5310-01-668-1663 (NIIN 01-668-1663) is a lock washer in Federal Supply Class 5310, Nuts And Washers — a washer, usually round, with a centrally-located hole. Manufacturer part number 01D2957H09 (Curtiss-Wright Electro-Mechanical, CAGE 4B9X1); also referenced as 3890AS003065-01-H09 (Naval Air Systems Command Managed); NL22SS (Nord Lock Inc).
NIIN assigned November 2017; DEMIL A (none required); ESD/EMI-sensitive; unit of issue EA (each), $0.11 gov standard price.