The EOTech Model 512 is perfect for anyone who wants fast target acquisition, reliability and durability without Night Vision capability. Mounts directly to a Weaver or MIL-STD 1913 rail. Accepts 2 AA batteries (supports lithion, alkaline or rechargable) and has a runtime of 1,000 hours (lithium) or 600 (alkaline) when ran at a brightness setting of 12. View 512 Operator's Manual PDF. Mfg: Eotech