A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 5905-00-188-9029
NSN 5925-01-342-3502
NSN 2925-01-052-0636
NSN 5960-00-140-9583
NSN 5935-00-655-4427
NSN 6150-01-487-5225
NSN 5905-01-625-1558
NSN 5950-00-862-8203
NSN 5998-01-423-7996
NSN 5998-01-229-6565
NSN 2925-01-256-8176
NSN 6145-00-129-9322