The Primary Arms MRS Mini Reflex Sight now features Autolive technology. This feature turns off after sitting still and will automatically turn on at the slightest motion helping to conserve battery life. The Mini Reflex Sight is optimized for full size carry pistols or competition guns as it features a large 24x17mm lens allowing for a quick and easy sight picture all while weighing under an ounce. Houses a bottom mounted CR2032 battery offering up to 40k hours of battery life on the medium setting.