This Timney set the standard for aftermarket trigger upgrades for the AR/M4 rifle A drop in, complete assembly trigger The trigger is factory tuned for pull weight, with no creep The shoes are adjustable for length of pull, cast and height for the ultimate in custom comfort and positive contact Ultra-reliable 5-pound hammer spring coupled with a crisp and zero creep 1.5 to 2 pound pull weight The 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 performance Compatible with all Military Spec Built Lowers