A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 5910-00-289-9894
NSN 6220-00-010-9301
NSN 6320-01-527-0211
NSN 5925-01-296-6699
NSN 5925-01-244-0705
NSN 6610-01-398-8092
NSN 5950-01-502-7019
NSN 5975-01-076-3656
NSN 6130-01-212-9912
NSN 6105-00-677-9803
NSN 6620-01-521-9710
NSN 7035-01-512-7776