A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 6145-00-466-4068
NSN 6645-01-549-8910
NSN 6610-01-435-4387
NSN 6220-00-823-6688
NSN 5965-00-007-7863
NSN 5895-01-432-6063
NSN 5996-00-373-9001
NSN 5950-01-602-5620
NSN 5930-01-165-4612
NSN 5910-01-076-6117
NSN 5999-01-463-1230
NSN 5998-00-871-9224