These are for replacing a installed standard trigger guard unless you have a complete parts kit - B5 Systems Reinforced Polymer Trigger Guard

After my experience I would recommend a Wheeler Engineering Trigger Guard Install Tool for Installing and Changing Trigger Guards. this item doesn't have the spring pin to retain the rear of the trigger guard because they are trying to save money and expect folks are doing an upgrade Vs a new build of a lower. great quality easy to install with the proper tool which you can buy here at optics Planet. looks great gives the rifle a better than stock look and is big enough for a gloved trigger finger. if you are doing a new build check and get the spring pin for a standard trigger guard in an AR parts build kit or a few to keep on hand for your builds. you will need an Allen key set for the set screw for the front mounting area of the trigger guard. very pleased great price and easy install would recommend this item to anybody who is looking to upgrade their AR style rifle in 5.56 or 7.62 calibers.