A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 5835-01-286-6499
NSN 5910-00-399-0734
NSN 4140-00-400-4872
NSN 5910-00-891-9507
NSN 5950-01-063-7638
NSN 5975-01-044-5419
NSN 5945-00-143-4422
NSN 6240-00-895-6461
NSN 5905-00-766-4927
NSN 5990-01-074-6549
NSN 4140-00-227-7609
NSN 6135-01-022-5427