A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 6220-01-010-3958
NSN 5945-01-010-0415
NSN 5990-00-529-8767
NSN 6620-01-651-0720
NSN 5975-00-578-0163
NSN 6685-00-350-0624
NSN 5996-00-107-5357
NSN 4140-01-064-1668
NSN 6320-01-519-8767
NSN 5930-00-483-0473
NSN 4140-00-215-8593
NSN 5965-01-147-5847