A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 5960-00-960-6805
NSN 5965-01-281-0458
NSN 6240-00-239-0159
NSN 5945-01-367-6469
NSN 5855-00-688-9954
NSN 6685-01-207-3358
NSN 2925-01-376-9236
NSN 6645-01-346-4505
NSN 6610-00-133-4508
NSN 7035-01-316-7860
NSN 5950-01-334-9753
NSN 6135-00-405-1989