Of course, every AR owners and builder knows that the trigger and hammer are held in by two pins that push through corresponding holes in the sides of the lower receiver. However, what some might not have experienced is the "walking" of these pins, caused by enlarged dimensions on the holes or wear. To prevent this issue, CMC Triggers designed its AR-15 Anti-Walk Pin Set, which enhances the reliability of your AR. Each CMC Triggers Anti-Walk Pin Set ships with two posts, four screws and the wrenches needed for assembly. The anti-walk pins can be installed and removed with ease, and there are no protrusions on the pin set that will interfere with the operation of an AR, even with gloved hands.