With aluminum alloy suitcase All metal construction with rubber armor provides a sure grip and great durability and also with a special prisms construction for extremely shockproof Highest brightness: better than 90% light transmission, fully broadband multi-layer coating optics The best optical performance requires the best optical material, by use of sepcial performance optical material We extremely raising the optical performance standard of the product Flat-field, distortion free, high resolution optics, equally sharp from center to edge, without any aberrations Maximum eye relief The dry nitrogen filled and O-ring sealed for 100% waterproof and fogproof, also completely fog-free vision from -40 to +70 Built-in reticle and compass Weight: 1,820g