The Midas Beam 3 MOA open red dot sight has the largest window of all of Athlon’s red dots, measuring in at 32mm by 44mm. The Fully Multi-Coated lenses reduce reflected light to increase light transmission, leading to crisp and colorful images, and the device has 50,000 hours of battery life in optimal conditions. Additionally, the Midas Beam has a built-in motion sensor to automatically wake up the device when motion is detected. Midas Beam 3 MOA Features: Fully Multi-Coated lenses Motion sensor Battery life of 50,000 hours (in optimal conditions) Athlon Scopes Athlon Midas Beam TSR1 3MOA Open Red Dot Sight 403073