The mepro m22 pro features a factory-installed light module that eliminates reticle washout and enhances low-light performance.With cutting-edge fiber-optic illumination for daylight visibility and premium swiss-manufactured tritium vials for nighttime clarity, this sight operates seamlessly in any lighting conditionno batteries required (unless you want it).Meprolight engineers designed a battery powered mechanism to enhance the reticle in extremely lowlight.The single cr2032 battery provides over 50,000 hours of use.The auto-adjuster reacts to ambient light to maintain a crisp reticle in the worst conditions.The transition between fiber-optic and tritium systems is instantaneous and automatic.Built with rugged, battle-proven construction, the mepro m22 pro meets or exceeds rigorous standards to perform flawlessly in the harshest environments.Its reliable in all weather conditions and compatible with night vision devices (nvds) and magnifiers for added versatility.With a ten-year warranty on tritium luminance, the mepro m22 pro delivers unmatched performance.Battery Size: CR2032Weight: 9.20 ozReticle: 10 MOA Red TriangleProofs: Waterproof