A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 6135-01-568-1367
NSN 4140-00-626-6470
NSN 6240-01-168-4533
NSN 5920-01-179-9739
NSN 5910-01-569-1172
NSN 6685-01-122-7471
NSN 6130-01-570-6758
NSN 6645-01-300-7611
NSN 6650-01-134-6186
NSN 6645-01-174-8116
NSN 5975-01-652-1407
NSN 5945-01-193-4312