Flat_Eric Ladies and gentlemen - we have a winner. Well gentlemen, don’t think there are any ladies here.
As Flat_Eric says, it’s for pulling the pins that secure the strings through the bridge on steel strung acoustic guitars. It slips over the head of the pin, then the collar is pushed down before pulling the pin out. It saves levering them out which risks damage to the bridge or pliers which risks damage to the pin.
More info here - proudly made in Murica. Snapz 2.0 (bigrockmfg.com)
