Oversized magwell guides the magazine into the gun quickly and smoothly to eliminate fumbling during reloads. Helps you make mag changes without taking your eyes off the target, and aids in maintaining a consistent hand position on the grip. Installs in minutes by inserting the brass channel insert in the bottom of the grip behind the magazine well and locking it with the machine screw (hex wrench included). Requires no permanent modification to pistol; remove and return to factory configuration at any time. Brass insert adds weight to aid in recoil control for faster follow-up shots. Will NOT fit generation 4 models.