These AR-15 anti-walk trigger and hammer pins replace the standard pins in a small-pin (.154") lower and use set-screw retention to keep both pins locked in place under recoil. Standard pins rely on the hammer and trigger spring legs to hold them in the receiver, and over time they can drift or walk out. An anti-walk set holds them positively, so the fire control group stays put. The pins are stainless steel, sized to the standard .154" diameter used by mil-spec AR-15 fire control groups. Each set covers both the trigger pin and the hammer pin, with the screws that hold them in the lower. Features: Anti-walk trigger and hammer pin set Set-screw retention stops pin walk under recoil Stainless steel construction Standard .154" small-pin diameter Drop-in swap for the factory trigger and hammer pins Fitment: Fits standard small-pin AR-15 lowers. NOT for large-pin (.170") Colt lowers. Some drop-in and cassette-style triggers use their own pin retention system, so confirm your trigger works with separate anti-walk pins before you install. After installing, function-check the trigger, hammer, and safety before firing.