A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 6130-01-106-8942
NSN 6650-00-510-3786
NSN 5950-01-552-9485
NSN 5935-00-300-2577
NSN 5910-01-095-2594
NSN 6645-01-306-9461
NSN 5985-01-303-4851
NSN 6150-00-133-5200
NSN 6645-01-443-0269
NSN 6650-00-166-7160
NSN 6220-01-104-1447
NSN 5920-01-540-8043