The 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.Finish: BlackType: TriggerModel: Tactical Trigger UnitSize: 22 CalMaterial: SteelAction: Semi-AutoTrigger: 4-4.5 lb