Aspherical lenses eliminate virtually all distortion _ Quick, smooth central focusing _ Tripod adaptable (with Product #7650) _ Diopter control to regulate vision imbalance _ BaK4 high index prisms _ Precision aligned sharp multicoated optics for bright, clear images _ Standard-size armored bodyThe new Nikon Action Extreme" binoculars feature an all-metal chassis with lens fittings housed in a tough, lightweight polycarbonate body shell. Like all Nikon All Terrain Binoculars, the EX is nitrogen-filled and O-ring sealed for total waterproof, fogproof and shockproof performance in any environment. The binocular bodies are ergonomically shaped, tripod adaptable and are rubber coated for a non-slip grip, whether wet or dry.The new Extreme ATB offerings utilize high-resolution lenses and prism systems crafted from Nikons exclusive Eco Glass", which is made without the use of arsenic or lead. This lens system provides an extremely clear, distortion-free image over the entire field of view. The lens elements each incorporate multi-layered anti-reflective coatings formulated to deliver optimum brightness, high contrast, true color rendition and flare-free viewing in most lighting conditions. The Extreme" series binoculars each feature a unique, click-stop eyecup design that not only delivers long eye relief, but also allows for variable eye relief that is customizable to the users own eyes and eyeglasses. The binoculars are central focus with a diopter control to correct for normal right/left eye vision imbalance.The Extreme ATBs all feature Apparent Angles of view that exceed 65 degrees, making them true Wide Angle binoculars while two of the models, the 7x35 and 8x40, will provide a field of view of over 420 at 1,000 yards, making them true wide field binoculars.