5310-00-685-3682 (FFW100)
NSN 5310-00-685-3682 (NIIN 00-685-3682) is a lock washer in Federal Supply Class 5310, Nuts And Washers — a washer, usually round, with a centrally-located hole. Manufacturer part number FFW100 (Federal Specifications Promulgated, CAGE 81348); also referenced as N416P21 (General Electric Company); 636106-000 (Bae Systems Information And); 373-0044-00, 373-0044-000 (Rockwell Collins, Inc.).
Key specs: 40 to 50 rockwell c hardness; full characteristics table below. NIIN assigned January 1963; DEMIL A (none required); unit of issue HD (hundred), $1.96 gov standard price; ships at 1 lb / 0.1 cu ft. Supersedes 5310-00-262-3636 (1976), 5310-00-261-7148 (2025).