A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 5999-01-121-9531
NSN 6135-01-408-0313
NSN 5910-01-573-6538
NSN 5905-01-275-2209
NSN 5920-01-633-6646
NSN 5975-00-373-5066
NSN 6135-01-502-5787
NSN 5925-01-442-5795
NSN 6610-01-352-5500
NSN 5998-00-156-2574
NSN 6685-01-139-6731
NSN 6105-01-484-0233