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
NSN 6240-01-007-6870
NSN 5960-01-361-6543
NSN 5998-01-535-0642
NSN 4140-01-505-3753
NSN 6135-01-333-6737
NSN 6650-00-497-7913
NSN 4140-00-597-5260
NSN 6110-01-245-8995
NSN 5835-00-834-1286
NSN 6320-01-451-0821
NSN 5905-01-613-6137