Sophisticated rubber armored exterior design provides shock resistance and a firm comfortable grip. Locking diopter control maintains your personal setting. Oil/Water repellent coating - applied to both eyepiece and objective lens surfaces. Nikon?s Legendary ED (Extra-low Dispersion)Glass Lenses. Waterproof (up to 1m/3.3ft for 10 minutes) and nitrogen-purged for fog-free performance