The Bullet Proof Slide Stop for 45 ACP takes an unbelievable pounding in a 1911 Auto making it vulnerable to breakage and wear. Bullet Proof Slide Stops are fully machined from solid stainless steel bar stock with extra metal left in critical areas for added durability, but the real key to a Bullet Proof Slide Stop is the material. Bullet Proof Slide Stops have a built-in detent, serrated top and maximum tolerance shaft. This is a drop-in part requiring no fitting in properly manufactured 1911 Autos. It fits All Codes in .45 ACP Pkg.