Sig's Romeo3XL open reflex sight is the ideal sighting solution for MSR rifles, shotguns, carbines, submachine guns, and full size handguns. It features a high transmittance red notch reflector for excellent brightness, and a 6 MOA red dot with multiple intensity settings ensures rapid target engagement under a full range of lighting conditions. The large 35mm lens offers unparalleled field of view in an open reflex sight. The Romeo3Xl is constructed of aluminum and comes with a Picatinny rail.