A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 5999-01-592-3882
NSN 5905-00-998-2943
NSN 6620-01-068-4498
NSN 5855-00-237-4088
NSN 5920-00-069-7624
NSN 5910-01-411-5366
NSN 5905-00-482-0595
NSN 5965-00-910-3233
NSN 5965-01-600-0566
NSN 5935-01-573-8833
NSN 5950-01-429-8741
NSN 6320-01-340-4112