Material: metal With rubber armor provides sure grip and great durability Special prisms construction for extremely shockproof Highest brightness - better than 90% light transmission, fully broadband multi-layer coating optics Best optical performance requires best optical material, by use of special performance optical material Flat-field, distortion free, high resolution optics - equally sharp from center to edge, without any aberrations Maximum eye relief Dry nitrogen filled and O-ring sealed for 100% waterproof and fog proof, completely fog-free vision from -40 to +70°C Optional built-in reticule and compass Size: 7 x 50, 10 x 50, 10.5 x 70 and 15 x 70cm in our hunting binoculars for hunting