A bent spring metal washer with a centrally located hole. It is designed to exert pressure axially when assembled in place.
NSN 5985-01-283-2515
NSN 5999-00-157-8163
NSN 2925-01-570-8065
NSN 5895-01-316-3148
NSN 6610-01-209-5798
NSN 6645-01-487-8227
NSN 6620-00-010-1415
NSN 6320-01-659-2819
NSN 6135-01-604-8739
NSN 5895-01-607-7238
NSN 5835-01-442-6482
NSN 5835-01-199-1683