This a Pro Series standard 9mm firing pin .064"-.068" diameter pin. Precision machined from solid 4150 steel alloy bar stock and heat-treated. Made for 9mm / 10mm / 38 Super and 40 S&W 1911 pistols. Is also used in higher quality 45 acp pistols with the 9mm firing pin hole machined in the slide. The smaller hole diameter helps with guarding against primer pocket cratering, which becomes more present with hotter loads and higher pressure cartridges. . Made for most all 1911 Colt style pistols and Clones. Will work with both 70 series and 80 Series pistols & extra clearance is machined in pin for Kimber style firing pin block systems on Kimber II style pistols. Black Oxide finished, Lifetime warranty.