A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 6145-01-207-4644
NSN 6110-01-588-5146
NSN 5895-01-131-4804
NSN 5965-01-559-1898
NSN 5960-01-215-9232
NSN 6650-00-312-1200
NSN 2925-00-530-3673
NSN 5985-01-343-8722
NSN 5990-00-806-3556
NSN 6145-01-357-3971
NSN 5930-00-267-1921
NSN 4140-01-025-9699