Manufactured from top grade tool steel to provide precise fit and reliable, consistent function under the most demanding conditions. Each part is wire EDM'd and CNC machined for a precise +/- .0005" tolerance then heat treated to Rc 53 - 56, then honed and mirror polished to give Extreme Service in your pistol. All of Harrison and Design Consulting's hammers have a prepped full cock notch that's .020" deep and a captive half cock notch that's full width, per the original prints. It can be successfully installed in all 1911s whether having a firing pin safety or not. The hammer is slightly narrowed to avoid unwanted contact with the slide or ejector an Mfg: Harrison Design & Consulting