Wilson Combat TRTTU3G Tactical Trigger Unit 3-Gun Drop-in Trigger with 3.50-4 lbs Draw Weight & Black Finish for AR-PlatformThe Tactical Trigger Unit is an all new modular trigger unit that can be easily installed in any AR pattern rifle by the end user in less than 1 minute without tools or even removing your selector. Wilson Combat has created a drop in trigger unit with an ultra crisp trigger pull that does not require any fine tuning or adjustment by the end user, the ttu is a totally self contained trigger module.