A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 6220-00-852-0367
NSN 2925-01-271-8727
NSN 6610-01-554-3159
NSN 5985-00-361-8863
NSN 5925-01-197-4693
NSN 6220-01-483-2098
NSN 6240-01-648-2327
NSN 5950-00-424-9646
NSN 5855-01-380-2708
NSN 5945-00-152-4862
NSN 5915-01-353-5442
NSN 6150-01-480-8727