5310-01-042-5580 (583150)
NSN 5310-01-042-5580 (NIIN 01-042-5580) is a lock washer in Federal Supply Class 5310, Nuts And Washers — a washer, usually round, with a centrally-located hole. Manufacturer part number 583150 (Army Weapons Command Attn, CAGE 21450); also referenced as 98449A006 (Mcmaster-Carr Supply Co).
NIIN assigned June 1977; DEMIL A (none required); unit of issue MX, $26.64 gov standard price; ships at 0.01 lb / 0.0005 cu ft.