A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 6645-01-567-1049
NSN 5930-00-013-1127
NSN 5895-00-900-5449
NSN 5999-00-212-3555
NSN 6110-01-571-7987
NSN 5975-01-074-7860
NSN 5920-00-126-1873
NSN 6130-00-371-2749
NSN 5990-01-294-6198
NSN 5945-00-681-0371
NSN 2925-01-295-9337
NSN 5925-01-123-9866