A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 6610-01-209-2524
NSN 5835-01-159-9088
NSN 5990-01-552-1503
NSN 6150-01-094-1654
NSN 5960-01-491-9916
NSN 5996-00-903-3224
NSN 5910-01-072-3256
NSN 6220-01-651-9331
NSN 5975-01-473-1562
NSN 5960-01-231-6502
NSN 6130-01-101-2148
NSN 5905-01-217-2454