The Hiperfire EDT Sharp Shooter Trigger is a significant AR upgrade. The single stage semi-auto trigger is a curved style with a unique Backbone feature, with medium pull weights (4.5 - 5.5 lbs) that offer smooth and accurate performance. This trigger offers a SwingFast Hammer Head with faster lock-up and MIL++ Heavy Duty Springs with very hard hammer strikes with high power touch off for ultimate accuracy, crisp trigger break, short over-travel, and very positive reset, this trigger is ideal for military upgrades, LE/SWAT, & personal utility. Features: a Radical Sear Mechanics a SwingFast Hammer Head a Mil++ Heavy Duty Hammer Springs a Curved Trigger with a Backbone