Nikon Monarch HG 10X42 Binoculars Overview First is the use of lead- and arsenic-free extra-low dispersion (ED) glass in the lens elements to correct chromatic and spherical aberrations. Next are phase-corrected and dielectric-coated roof prisms, which further limit internal light loss and interference and improve image contrast. The optical path is fully multi-coated with anti-reflection coatings, which increase light transmission, image contrast, and sharpness and provide true colour rendition. Finally is the use of Nikon's field-flattener system, which eliminates the distortion common at the lens edges, producing crisp details along the far periphery of the wide field of view. This all translates to bright and clear, high-contrast images with accurate colour across the wide field of view with a reduced appearance of visible handshake—especially at low light such as early morning and late evening, and under heavily overcast skies. The chassis is built with a short bridge design, which presents a more gripping surface and helps to reduce the overall weight. Made to survive use outdoors, the optical tubes are nitrogen-filled and O-ring sealed to make them not only fogproof when moving between extreme temperature changes but also waterproof and submersible. The exterior has textured, rubberized panels that protect against knocks and drops and offer a slip-resistant grip for sure handling in cold and wet conditions. Nikon includes tethered objective lens covers and ocular rain guards to ensure they cannot be lost easily and are ready for use at a moment's notice.