Put more accuracy on top of your firearm without having to put more into it. The Holosun HS403R Micro Reflex Red Dot Sight employs ultra-efficient LED technology that squeezes up to 100,000 hours of life from a single battery and is 4x more efficient at the highest brightness setting. Easy-to-operate Rheostat dial adjusts brightness settings quickly. Multi-coated lens offer a parallax-free sight picture with unlimited eye relief. Durable aluminum construction is unaffected by extreme weather conditions and a 1/3 co-witness and low mount are both included.