5310-01-565-8341 (5060021513)
NSN 5310-01-565-8341 (NIIN 01-565-8341) is a lock washer in Federal Supply Class 5310, Nuts And Washers — a washer, usually round, with a centrally-located hole. Manufacturer part number 5060021513 (Instock Fasteners, CAGE 1PCW1); also referenced as MIL-001-459 (Fascan International, Inc.).
NIIN assigned August 2008; DEMIL A (none required); ESD/EMI-sensitive; unit of issue EA (each), $25.27 gov standard price.