A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 6645-01-480-0662
NSN 6645-01-577-5891
NSN 5965-01-543-4934
NSN 6150-01-074-2577
NSN 5915-01-437-0950
NSN 5835-00-247-0161
NSN 5950-01-330-7693
NSN 6145-01-220-9158
NSN 5910-01-499-1859
NSN 6645-00-069-4381
NSN 5915-00-164-5120
NSN 5965-00-693-8829