A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 5910-00-411-7560
NSN 6220-00-156-0860
NSN 6650-01-384-1657
NSN 6135-00-152-8729
NSN 7035-01-563-7731
NSN 5835-01-285-8650
NSN 6320-01-082-2970
NSN 5905-00-903-1072
NSN 5965-00-959-8162
NSN 5950-01-474-2016
NSN 5950-01-158-6865
NSN 6645-00-269-2764