Bushnell H2O Waterproof/Fogproof Compact Roof Prism Binocular, 12x 25mm O-ring sealed & nitrogen purged BaK-4 prisms Multicoated optics for superior light transmission 100% waterproof O-ring sealed & nitrogen purged 100% waterproof, O-ring sealed and nitrogen purged for reliable, fog-free performance BaK-4 prisms and multi-coated optics offer crisp clear images with improved light transmission Non-slip rubber armor and Soft Texture Grip absorbs shock and provides a firm grip 12x magnification and 25mm objective diameter; 20-foot close focus distance; 9mm eye relief Large center-focus knob for easy adjustments; Twist-up eyecups; Limited lifetime warranty