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 6685-01-072-1955
NSN 5950-01-448-4230
NSN 5835-00-409-8355
NSN 5930-01-441-0099
NSN 7035-01-220-6392
NSN 6220-01-247-4381
NSN 5965-01-341-4036
NSN 5960-01-105-5131
NSN 5920-01-085-8374
NSN 5915-01-145-0919
NSN 6135-01-648-2284
NSN 6135-01-255-9129