A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 5965-00-153-5216
NSN 6650-00-334-5901
NSN 6145-01-176-9842
NSN 6620-01-032-3937
NSN 5999-01-541-8446
NSN 5996-00-525-1777
NSN 5960-01-564-5044
NSN 6145-00-441-2512
NSN 5975-01-322-6464
NSN 6130-00-812-6175
NSN 6320-01-431-4359
NSN 5925-01-126-6288