5310-00-655-9504 (FFW84CLASSASTYLE1)
NSN 5310-00-655-9504 (NIIN 00-655-9504) is a lock washer in Federal Supply Class 5310, Nuts And Washers — a washer, usually round, with a centrally-located hole. Manufacturer part number FFW84CLASSASTYLE1 (Federal Specifications Promulgated, CAGE 81348); also referenced as MS35337-51 (Military Standards).
Key specs: 45 to 53 rockwell c hardness; full characteristics table below. NIIN assigned January 1963; DEMIL A (none required). Related NSN 5310-00-584-7888.