A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 5945-00-399-5230
NSN 5920-01-240-6373
NSN 5960-00-269-3023
NSN 6610-01-253-5112
NSN 6685-01-251-3797
NSN 6645-01-519-2220
NSN 5910-01-105-8504
NSN 6135-01-384-3915
NSN 5895-01-050-8909
NSN 6610-00-398-9673
NSN 4140-00-658-7271
NSN 6135-01-458-3851