The 552 is Eotech&';s most affordable night vision-compatible sight and it partners with most night vision-devices. The 552 is designed to increase your speed to target even after the sun goes down. Features 20 daylight setting and 10 Night Vision Settings; water and weather resistant; mount is compatible with both Weaver/Picatinny rails. Includes quick start guide, batteries and protective case. *Note- The XR308 reticle was designed specifically for the military M240 machine gun. It should be used with .308 cal with 150 gr M59 FMJ at roughly 2,800 fps with a 24.8" barrel. Features Auto Shut Down at 8 hours.