A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 5999-01-468-6530
NSN 6240-01-536-3604
NSN 5835-01-381-2683
NSN 6150-00-828-7136
NSN 5950-00-715-2977
NSN 5999-01-554-8428
NSN 5855-01-406-4821
NSN 6645-01-450-7271
NSN 5998-01-024-2717
NSN 5945-01-505-8698
NSN 5960-01-228-7092
NSN 5920-00-922-1094