A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 5835-01-193-6192
NSN 5855-00-247-7219
NSN 5910-00-333-0329
NSN 5930-01-009-5144
NSN 6145-00-721-4066
NSN 5950-00-535-9682
NSN 6240-00-712-3090
NSN 6150-01-368-6958
NSN 5930-00-672-5948
NSN 5895-01-048-8618
NSN 6150-00-172-5841
NSN 2925-00-899-4261