Endeavor ED II 8420 Premium Japanese Extra-low Dispersion (ED) glass provides incredibly bright edge-to-edge clarity and true life color. Excellent near focus=2m. 3-stops eyecups with long eye relief. Locking Diopter Ring with +4D~-4D adjustment. Light weight durable Magnesium body. Japanese Extra-low Dispersion (ED) glass (νd >94) Large view angle and minimum near focus Ergonomic Center Focus Wheel Memorable right-eye diopter settings and Adjustable 3 stage twist-out eye cups Light weight durable Magnesium alloy body