The Xtended Twilight Lens System places extra emphasis on matching coatings to glass indices to achieve the best possible transmission of the blue/violet spectrum, without sacrificing the color balanced light transmission across the visual spectrum of the Index Matched Lens System. Your eye is already handicapped when it comes to seeing the blue/violet spectrum, and if your scope is cutting too much of it out, soon you won't be seeing anything. The challenge is that in twilight conditions, green light disappears and blue/violet light takes over. When most scope manufacturers quote percentage of light transmission, they usually mean at 550 nm, the green wavelength where the human eye is most sensitive. It goes a step further than even the Index Matched Lens System, using Leupold's index matched glass with wavelength specific lens coatings designed to optimize the transmission of low-light wavelengths. Now your hunt can reach further into the twilight than ever before possible, with our exclusive new Xtended Twilight Lens System. Engineered for carbine platforms, the rugged, compact and combat-ready Mark 4 HAMR is designed for precise mid-range distance marksmanship and fast target acquisition in bright daylight, low light and at night.