A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 5975-00-489-8744
NSN 5965-01-125-5367
NSN 5930-01-224-4062
NSN 5998-00-451-8841
NSN 6110-01-088-8143
NSN 5999-01-100-1872
NSN 6150-01-010-3727
NSN 6145-01-581-3561
NSN 6220-01-150-9231
NSN 5925-00-905-5135
NSN 5975-01-474-5631
NSN 5945-01-068-3503