Hiperfire Enhanced Duty Sharp Shooter Single Stage Trigger - HIPERFIRE knows triggers. They are the most intimate contact we have with our firearm. Triggers affect what we "feel" in and about our gun and its ultimate performance that must take the preeminent place over any other firearm feature including optics, barrels, ammunition, and furniture. HIPERFIRE has taken triggers for the AR15/10 to the next level. We have had a big impact within 3-gun circles because we came out of nowhere with no marketing, no reputation, no name. What we did have were triggers that shooters could only dream about. Significant AR Upgrade Single Stage Semi-Auto Radical Sear Mechanics(TM) Medium Weights, 4 1/2 and 5 1/2 lb. Pulls Smooth Accurate SwingFast Hammer Head(TM) MIL++ Heavy Duty Hammer Springs Recommended for use in AR-15 and AR-10 variants NOT recommended for use in AR-9/PCC variants Made In The USA