Timney Triggers Impact Trigger, Fits AR-15, Black, Billet Machined Parts, 3 LB Break, Not Compatible with AR-10 IMPACT AR-ST Timney has been asked for an AR trigger at a lower price without compromising on quality for budget-build AR's. You asked" Timney listened. The Impact will give you a crisp" clean" 3 pound break and will drop in to all Mil-Spec AR's. All components are captive in the lightweight" aluminum alloy housing. Hammer is wire-EDM machined from S7 tool steel that combines hardness to resist wear with superior impact resistance to withstand heavy use without chipping or breaking. Other components are EDM cut from A2 tool steel" then heat treated to Rc 56-60 for long service life. Installs using your rifle's original hammer/trigger pins" the proprietary design eliminates pin walkout.