Fits Gen 1-4 System uses, Polished & Enhanced Trigger Bar, & Shoe. Also features a polished Trigger Shark (-) Minus connector for reduced, and optimum break weight (due to production delays, connector could be replaced with a SS-22 connector which nets the same results). Package comes with a Hex Key for adjustments of the Pre-Travel.Several modifications and enhancements on the trigger bar to maximize the smooth, drag free movement of the bar over polymer and metal for optimum action. Shoe is lasered for a combat ready feel, with multiple enhancements for improved performance. Including a slight trimming of the safety tab for a better feel. Now you have the trigger system you trust, with the enhancements to improve its performance for all applications.