ArmsTAC&reg; Red Dot Sight Tactical Open Reflex Sight 4 Reticle Weaver-Picatinny Rail Mount with ArmsTAC&reg; Lifetime Warranty Red Dot Sight with 4 different reticles and 7 brightness settings. Open red dot reflex design with windage and elevation adjustments Mounts onto standard weaver and picatinny rails 1X magnification, 33-millimeter objective aperture, 24 x 34 objective diameter, three-inch length, and 4.2-ounce weight Comes with Lifestime manufacture's warranty