A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 6105-00-459-5261
NSN 5920-01-476-9042
NSN 6110-01-505-2074
NSN 6150-00-955-5549
NSN 6320-01-513-9166
NSN 6645-01-487-8227
NSN 5905-01-437-3338
NSN 6620-00-401-8489
NSN 6110-00-202-1021
NSN 5985-01-315-6206
NSN 5925-00-976-4883
NSN 6620-01-601-4314