Regal ED Flat Field Binoculars build on the success of Celestron's customer-favorite RegalED spotting scope line. With both ED objective lenses and flat field lenses, these binoculars provide sharp, expansive views and of a high degree of accurate color resolution. As Celestron's new premiere line of performance-level field binoculars, the RegalED Flat Field Binoculars are designed with the most selective of all binocular users in mind: birders. From their vivid, true-to-life color resolution, expansive fields of view for ease of locating fast moving objects, and 4.9 foot close focus distance to get an even closer look when a subject suddenly pops out of the bushes and right on the trail in front of you, the RegalED binoculars provide everything needed for the most selective of binocular users - which ensures that they're up to the challenge across a wide-range of other activities. ED Glass Objective Lenses Extra-Low Dispersion (ED) glass virtually eliminates chromatic aberration, also known as color fringing, a distracting visual effect produced when different wavelengths of light disperse while transiting optical lenses. By reducing dispersion, the RegalED binoculars provide images with outstanding, true-to-life color. But not all ED binoculars are created equal. Celestron's high quality ED glass objective lenses deliver visibly brighter, sharper images compared to non-ED binoculars. The difference is especially apparent in low light conditions, such as at dawn or dusk. Flat Field Technology In addition to using ED glass, the Regalfeatures flat field optical technology that counter-balances the normal visual field curvature convex lenses naturally show, delivering an expansive linear image all the way to the edges of the field of view. Coatings and Prisms RegalED features fully multi-coated optics. A binocular can be considered "fully multi-coated" when all air-to-glass surfaces are coated with multiple layers of anti-reflectivity coatings so that the maximum amount of light passes through the glass to the eye. The prisms inside RegalED are made of high quality BaK-4 glass with phase coatings applied so that more light is reflected off their internal faces and passes through to the eye. Taken together, the fully multi-coated lenses and BaK-4 prisms maximize light transmission for the remarkably bright, highly detailed images. The ED objective lenses further enhance these features, especially in low light conditions. The Body The well-balanced, ergonomic industrial design magnesium alloy body protects your RegalED binoculars from damage without weighing you down. Viewing through RegalED is comfortable for both eyeglass wearers and non-eyeglass wearers, thanks to the durable metal twist-up eyecups. Twist through multiple click stops to find the position that works best for you. What's more, the binocular is fully waterproof and filled with dry nitrogen gas to prevent internal fogging of lenses. RegalED can stand up to even the toughest outdoor...