A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 5910-00-513-4578
NSN 6320-00-213-0477
NSN 5990-01-463-2279
NSN 6645-00-145-6411
NSN 6135-01-494-3607
NSN 5965-00-806-7593
NSN 5905-00-617-3586
NSN 6130-00-865-6558
NSN 5960-01-552-0862
NSN 6130-01-211-7905
NSN 5920-01-056-5481
NSN 6685-01-106-0962