5310-00-209-1337 (FFW84CLASSCSTYLE2)
NSN 5310-00-209-1337 (NIIN 00-209-1337) is a lock washer in Federal Supply Class 5310, Nuts And Washers — a washer, usually round, with a centrally-located hole. Manufacturer part number FFW84CLASSCSTYLE2 (Federal Specifications Promulgated, CAGE 81348).
Key specs: 35 to 43 rockwell c hardness; full characteristics table below. NIIN assigned January 1963; DEMIL A (none required). Related NSN 5310-00-973-8786.