Use to quickly install pivot pin without damage to the firearm. Simple to Use A: Place the pivot pin tool over the pin housing on the lower receiver, then insert the large pivot tool pin. B: Insert the spring first, then the detent into the pivot tool pin channel. Use the plunger to compress and hold them in place. C: Rotate the tool assembly 90° and carefully remove the plunger. D: Slide the pivot pin in as shown, remove the large tool pin, take off the tool fixture, and snap the pivot pin into the closed position.