The Mepro MMX3 micro magnifier is compact, lightweight magnifier that will extend your effective range of your red dot or 1x reflex sight. Weighing in at 6.1 it reduce the footprint, saving rail space and weight on your firearm. Elevation and windage dials provide precise FOV line of sight alignment. A wide FOV enables rapid target acquisition with both eyes open which is ideal where agility, and speed are of the utmost importance. The Mepro MMX3 micro magnifier attach to any MIL-STD-1913 rail directly behind your optic. When not in use the Mepro MMX3 can be "flipped" out of the way by depressing a pushbutton. Side Flip HIgh transparancy Optics Highly Durable Structure No Batteries Needed Two Rubber Covers Length 2.8" (70.6mm) Center Height 1.4" (36mm) Center Height with Riser 1.74" (44.4mm )