A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 5920-01-579-5219
NSN 5925-00-070-5011
NSN 6150-01-072-5818
NSN 5960-01-541-5734
NSN 5855-01-291-6790
NSN 6620-01-180-2687
NSN 5975-01-418-8710
NSN 5965-01-100-2591
NSN 7035-00-155-9513
NSN 5985-01-634-0635
NSN 2925-01-257-0695
NSN 6135-01-471-7325