Elliptical locking feature id
A soft metal or nonmetal sleeve, designed to mate with a pin-rivet. it may include an external wrenching facility which breaks off at a perdetermined torque to form a head.
NSN 5930-00-581-4797
NSN 5945-01-450-8456
NSN 6620-01-446-4797
NSN 5855-00-869-3635
NSN 5895-01-167-3911
NSN 6105-00-999-2654
NSN 5985-00-924-4730
NSN 6620-01-263-6697
NSN 6620-01-426-2220
NSN 5855-01-432-4401
NSN 6150-00-876-9289
NSN 5990-01-219-2703