ED Glass - ED glass gives you an image with little or no chromatic fringe so the final result brings a clearer and sharper image to your eyes ESP Dielectric Coating is a multi layer prism coating that reflects over 99% of the light to your eyes bringing you a clear, bright image that displays accurate color reproduction. Advanced FMC - Advanced Fully Multi-Coated lenses gives you better light transmission to bring optimum brightness and true color across the entire light spectrum. Argon Purged - Argon purging gives you better waterproofing and thermal stability and Field of view Angular -8.1 degree Long eye relief can be particularly important for eyeglass wearers because longer eye relief allows them to still see the entire field of view.Field Of View M @1000 METERS:144 m