A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 5965-01-193-5221
NSN 6135-01-579-3534
NSN 5975-01-133-7789
NSN 5905-01-595-7667
NSN 5935-01-384-6985
NSN 6610-01-486-7954
NSN 5996-01-397-6457
NSN 5895-01-359-2886
NSN 5960-00-246-9749
NSN 5915-01-281-1570
NSN 5930-00-910-4033
NSN 5855-00-466-2309