Carter Brass Pull Pin #PKK-027
Used with the Pull Bar (Rod Puller) which the Pull Rod hooks around.
Also referred to as a 'Dog Bone'.
Put a drop of light oil (i.e. 3-In-One) on these Pull Pins every 6 months (or more depending upon your playing schedule), to extend their life, as they wear out faster if not lubricated. They can break or go out of round & cause tuning problems.