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 6150-00-537-5538
NSN 5945-01-278-9211
NSN 6610-00-904-4839
NSN 6150-01-271-5021
NSN 6645-01-487-6282
NSN 6220-01-568-2258
NSN 5835-00-958-6231
NSN 6145-01-462-2460
NSN 7035-01-445-3563
NSN 6645-01-242-4826
NSN 5950-01-239-0566
NSN 5990-01-651-6364