A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 6135-01-648-4875
NSN 6685-00-474-5721
NSN 5998-00-952-2562
NSN 5935-01-111-1669
NSN 5905-01-442-7682
NSN 5945-01-025-0504
NSN 5990-00-356-8911
NSN 6650-00-464-1183
NSN 7035-01-151-0265
NSN 5996-01-386-0063
NSN 5996-01-538-2841
NSN 6145-00-925-2004