LED (Light Emitting Diode) 100% Safe for the Eyes. Unlimited eye relief for flexible mounting. Electronic control panel for turning Green Dot On/Off and for adjusting Green dot brightness levels. Side rail for mounting accessories like a flashlight or laser. Optic includes a pair of micro backup iron sights on top of the optic. Optic height above the rail is set to the popular 1.5" AR15 optics height. Powered by 3 Volt Lithium Batteries (CR123A included) for longer battery life. Black anodized aluminum body. Dot Size: 3 MOA.