Drop-In Skeletonized Trigger Features Now shooters can replace their AR Trigger with one that is smooth and breaks crisp. he trigger is factory preset with a pull weight of 4 lbs. Installation is quick and no adjustments are necessary 100 percent true drop-in trigger. The trigger module installs using your rifle s original hammer/trigger pins and the proprietary design eliminates pin rotation and walkout. Drop-In Skeletonized Trigger Specifications Timney Drop-In Skeletonized Trigger AR-15 4 lb #664S Small Pin