The Timney AR15 Small Pin Skeletonized Trigger will have you thinking that you're pulling the trigger on a precision bolt action rifle rather than a modern sporting rifle. The Timney AR15 Drop-In Trigger provides a crisp and creepless pull with no gun-smithing, fitting, or adjusting required. All components of the trigger are encased in the lightweight but durable aluminum housing. The hammer is machined from S7 tool steel providing superb resistance to impact and the other components of the are cut from A2 tool and heat treated to ensure a long service life. CompatibilityAll Military Spec Built LowersAR-556Mossberg MMR HunterMossberg MMR TacticalMossberg MMR Tactical w/sightsSR-556SR-556 CarbineSR-556 VTSR-556-ETimney AR-15 Triggers are designed to fit all mil-spec AR-15/ M4 platforms, including the large pin Colt Rifles made in the 90’s Timney AR15 Large Pin Skeletonized 4.5 lb Trigger 665L