3.5lb Single-stage trigger system; Allows you shoot more accurately with less effort; Ultra-smooth break with a crisp, clean release; Fits small pin size (.154); Quick reset and low overtravel for enhanced speed; Interior parts are S7 tool steel with heavy-hit hardening then black nitride finished for enhanced strength and corrosion resistance; Lightened trigger pull (3.5-lb. pull weight); Lightened hammer; Drop safety feature; Self-contained design makes it easy and quick to install with no fine-tuning needed