The Holosun HS507C-X2-ACSS is a new generation of pistol red dot sight packed full of features like the multiple reticle system, solar failsafe, and shake awake technology to ensure your reflex sight is always operational when you need it. On top of the two battery-saving techniques, the HS507C-X2 reflex sight features up to 20,000 hours of Battery Life on setting 6 with the CR1632 battery. This battery is located in a convenient tray that slides out and allows you to easily change it without having to remove the optic from your pistol. This model features the revolutionary, patented ACSS Vulcan reticle with an outer circle. It features 7075-T6 aluminum construction with an anodized black finish and fully multicoated glass for long-term durability.