The Timney AR-10 trigger is a self-contained 100% drop-in unit ready to install in an AR-10 rifle for an exceptionally smooth crisp single-stage trigger pull. No gunsmithing fitting or adjusting required. Pull weight is factory set at 4 pounds. Lightweight 6061 T6 alloy housing is anodized for superior durability. Hammer is EDM machined from S7 tool steel that combines hardness to resist wear with superior impact resistance to withstand heavy use without chipping or breaking. Finally a Teflon Nickel coating is applied to the hammer to deliver a super smooth trigger pull with superior lubricity. Other components are EDM cut from A2 tool steel then heat treated to Rc 56-60 for longer service life. Trigger Module installs using your rifle's original hammer/trigger pins; proprietary design eliminates pin rotation and walkout.