Primary Arms 3X Red Dot Magnifier Gen III 3X RED DOT MAGNIFIER: Place the magnifier behind your red dot or holographic reflex sight to instantly magnify the sight picture at 3x power. INTEGRATED DIOPTER: Provides a fast focus ability to keep the image clear. AZIMUTH AND ELEVATION ADJUSTMENTS: Keep the dot centered in your field of view. MOUNT COMPATIBILITY: Mounts chosen need to be capable of interfacing with the 30mm ring on this magnifier because the objective is larger than the 30mm mounting area.