A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 6220-00-056-6751
NSN 6685-01-250-2669
NSN 6110-01-386-4055
NSN 5905-01-302-0833
NSN 5999-01-630-2655
NSN 6685-00-166-0057
NSN 5920-01-278-0600
NSN 5998-01-084-9123
NSN 7035-00-946-2642
NSN 5915-01-144-2319
NSN 5950-00-395-1312
NSN 2925-01-205-4584