The Breach 1.0 is an ATF approved pistol brace designed to be low profile and easy to install for the end-user. It is built to fit AR-15 pistol buffer tubes with a diameter of 1.25″. The Breach requires no special extensions or tools to install. This sleek and lightweight brace is perfect for any AR-15 pistol build. For your safety, Trinity Force recommends a qualified gunsmith/installer install this part. Always make sure the firearm is unloaded and pointed in a safe direction when working.