Apex Tactical’s Polymer Action Enhancement Trigger Kit is engineered to give the S&W M&P 9mm / .40 a smoother, more consistent, lighter (5 to 5-1/2 lb.) trigger pull with a shorter reset than the factory trigger. The Apex M&P 9mm / .40 Polymer Action Enhancement Trigger Kit reduces trigger pre-travel and over-travel by approximately 20%, while the rounded face gives the shooter’s finger a comfortable surface when firing. Keeps safe trigger pull weight for duty/carry applications Center mounted pivoting safety maintains factory safety values Works with all S&W M&P pistols in 9mm and .40 S&W Will NOT work in M&P45, M&P M2.0, M&P Shield, or .22 LR models The Apex M&P 9mm/.40 Polymer Action Enhancement Trigger Kit is designed to drop in and normally should not require further gunsmithing. However, armorer or gunsmith installation is recommended. Kit includes: trigger, heavy duty sear spring, fully machined sear, duty/carry spring set, Ultimate Striker Block Kit, and slave pin for installing trigger return spring.