Tornado binoculars were built to withstand the hazards of marine activities. They will survive heavy weather, extreme temperatures and on-the-water use. Dry nitrogen Charged and sealed against moisture and internal fogging, they will even float if dropped overboard. They feature fully multicoated optics plus extra bright BaK-4 prisms. They can also be used in navigational aid with the illuminated built-in dampened compass. The range finding reticle, coupled with the built-in calculator, measures either your distance from or the size of faraway objects.