The FastFire 3 Reflex sight is light, small and tough, placing a powerful bright 3 MOA red dot on the target. It has three manual brightness settings and an automatic brightness setting with a top-mounted battery and upgraded windage and elevation adjustments. The ultimate CQB sight is great for mounting on a pistol, shotgun or rifle. Includes detachable Weaver/Picatinny mount. The 3 MOA dot is most popular with rifles, or anyone wanting more pin-point accuracy, as the smaller dot covers far less of the overall target area. The FastFire 3 will work with virtually every optics ready handgun. However, the Burris supplied mounting screws may not be the correct length for every single handgun. Please contact the firearm manufacturer for specific screw lengths necessary for correct mounting.