A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 5855-00-221-9435
NSN 6650-01-308-7284
NSN 5975-01-147-7645
NSN 6105-01-216-1617
NSN 6105-00-212-8013
NSN 6220-01-322-5660
NSN 6240-01-554-9952
NSN 5905-01-479-3414
NSN 6610-00-451-8840
NSN 6150-01-607-3997
NSN 5999-01-088-0253
NSN 6620-01-317-7849