Features: SPD has a dual power source. The Red Dot reflex optic can be powered by the sun via the top mounted solar cell or the included AA battery. Solar cells mounted on top of the reflex sight will power the red dot whenever there is sufficient sun light on the solar cells. The Red Dot automatically turns on when there is sufficient sun light. The SPD Red Dot can also be powered by the AA battery. AA battery should be used when there isn't enough sun light, when using the optics indoors, or when using the optic at night. The electronic control panel has a red LED indicator when the Red Dot is powered by the AA battery. Features an electronic control panel to turn on the Red Dot under AA battery power. You can adjust the brightness level up or down when powered by the battery. Red Dot centerline is at 1.5" AR15 height. Locking quick release Picatinny mount. Unlimited eye relief. LED 100% safe for the eyes. 2 MOA Red Dot has 5 levels of brightness. International orders will not include batteries. Specifications: MAGNIFICATION: 1X DOT SIZE: 2 MOA DOT COLOR: RED OBJECTIVE DIAMETER: 30MM WEIGHT: 11.7 LENGTH: 4.0" LENS COATING: RUBY BATTERY: AA