A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 6685-00-753-7429
NSN 6105-00-807-8986
NSN 5996-01-412-9232
NSN 6240-00-987-0977
NSN 7035-01-529-4603
NSN 5905-01-414-6970
NSN 6240-01-643-5990
NSN 5925-01-512-9060
NSN 6110-01-243-0446
NSN 6240-01-054-2289
NSN 7035-01-487-6481
NSN 6145-01-421-9343