Elftmann trigger ar-15 match pro curved pro lock 2.75-4lbs. FEATURES:CurvedAdjustable from 4lbs to 2 3/4lbsProprietary Threaded mounting system Compatible with ALL calibers - 5.56, 9mm, .308 Fits any mil-spec AR-15 (Standard pin size, no large pin Colt)Drop-Safe regardless of pull-weightVery short pull and reset allows for rapid follow up shots and greater accuracy Other Features: Fully adjustable 2.75-4# pull, aerospace grade sealed roller bearings on hammer & trigger rotation points.Made in usa lifetime guarantee, 100% drop-safe design, skeletonized trigger, proprietary threaded mounting system