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 6685-01-473-1997
NSN 6320-00-857-4073
NSN 5935-01-082-4339
NSN 5965-00-007-7863
NSN 5965-01-633-1281
NSN 5990-01-436-7191
NSN 5985-01-099-8416
NSN 6610-01-371-3006
NSN 6645-01-606-7684
NSN 5915-01-281-7553
NSN 7035-00-490-0485
NSN 5950-00-471-3750