A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 5975-00-204-9190
NSN 6150-00-659-7123
NSN 6130-01-382-2532
NSN 6685-01-364-8552
NSN 6685-01-051-3794
NSN 5965-01-360-6568
NSN 5990-01-632-0969
NSN 4140-01-476-5436
NSN 5996-01-325-8555
NSN 6220-01-540-8470
NSN 6240-01-023-7720
NSN 6645-01-414-8806