Apex Tactical Specialties Action Enhancement Trigger and Duty/Carry Kit for S&W M&P Shield. The Trigger Kit directly replaces the factory hinged trigger with a solid aluminum trigger body which reduces pre-travel and over-travel by approximately 20percent. It features a smooth face with a center mounted pivoting safety that maintains factory safety values. The Apex Duty/Carry Kit was designed to provide the S&W M&P Shield pistol owner a smooth consistent trigger pull that is approximately 2 lbs lighter (based on variations in factory tolerances) with the advantages of shorter over-travel and more detectable trigger reset. However armorer or gunsmith installation of the Ultimate Striker Block (USB) into the Shield slide is strongly recommended. Expected Results - Reduces trigger pull by approximately 2 lbs. - Smooth uptake and reset - Reduces pre-travel - Reduces over-travel - Reduced reset - Center mounted pivoting safety maintains factory safety values Notes If you are interested in a replacement trigger for the M&P Shield please see the Shield Duty/Carry Action Enhancement Trigger and Kit. For further information regarding the trigger itself please see Shield Action Enhancement Trigger. The Shield sight removal in order to install the USB Kit is extremely difficult. Removal requires delicate precision so as not to damage the sights or slide. We highly recommend having a competent gunsmith perform this task. Specifications for Apex Tactical Specialties Action Enhancement Trigger and Duty/Carry Kit for S&W M&P Shield: Manufacturer: Apex Tactical Specialties Color: Black Gun Make: Smith & Wesson Gun Model: Smith & Wesson M&P 40 Shield Smith & Wesson M&P 9 Shield Included Accessories: Standard Condition: New Package Contents: Apex Tactical Specialties Action Enhancement Trigger and Duty/Carry Kit for S&W M&P Shield (x1) Action Enhancement Trigger (x1) 2-Dot Fully Machined Sear (x1) Duty/Carry Sear Spring (x1) Duty/Carry Trigger Return Spring (x1) Ultimate Striker Block (x1) Striker Block Spring (x1) Apex Sight Tool (x1) Slave Pin What firearm models does the manufacturer say Apex Tactical Specialties Action Enhancement Trigger and Duty/Carry Kit for S&W M&P Shield is compatible with? The manufacturer suggests that Apex Tactical Specialties Action Enhancement Trigger and Duty/Carry Kit for S&W M&P Shield is compatible with Smith & Wesson M&P 9 Shield Smith & Wesson M&P 40 ShieldApex Tactical Specialties 100-051: Action Enhancement Trigger and Duty/Carry Kit for S&W M&P Shield