This Timney set the standard for aftermarket trigger upgrades for the AR/M4 rifleA drop in complete assembly triggerThe trigger is factory tuned for pull weight with no creepThe shoes are adjustable for length of pull cast and height for the ultimate in custom comfort and positive contactUltra-reliable 5-pound hammer spring coupled with a crisp and zero creep 1.5 to 2 pound pull weightThe Timney AR Calvin Elite offers a custom fit and lighter pull weight Trigger allows you to become more accurate with your rifle No gunsmith needed easy to install Ready for the range no adjustments needed Provides a custom fit for every shooter Optimal performanceCompatible with all Military Spec Built Lowers