5310-01-165-2389 (XB-E536)
NSN 5310-01-165-2389 (NIIN 01-165-2389) is a lock washer in Federal Supply Class 5310, Nuts And Washers — a washer, usually round, with a centrally-located hole. Manufacturer part number XB-E536 (Saf-Holland, Inc., CAGE 74410).
Key specs: 47 to 53 rockwell c hardness; full characteristics table below. NIIN assigned October 1983; DEMIL A (none required); unit of issue EA (each), $21.65 gov standard price.