By using CNC milled parts, there are no MIM or Powder Compaction Molding components and are engineered to tight Mil-Spec tolerances with the same components and materials used in service rifles. This premium Mil-Spec LPK's Trigger, Hammer, and Trigger Guard are polished 8620 steel magnesium and Black Oxide coated at the manufacturer, providing a smoother action with a superior crisp pull, compared to the typical Lower Parts Kits that includes a stainless steel trigger and hammer like an Anderson Lower Parts Kit.