5310-00-018-0440 (180440)
NSN 5310-00-018-0440 (NIIN 00-018-0440) is a lock washer in Federal Supply Class 5310, Nuts And Washers — a washer, usually round, with a centrally-located hole. Manufacturer part number 180440 (General Motors LLC, CAGE 7X677); also referenced as MILW6986 (Military Specifications); 7E07 (Clark Material Handling Company).
NIIN assigned January 1963; DEMIL A (none required). Related NSN 5310-00-883-8741.