Bushnell Bear Grylls 10 x 42mm Roof Prism Waterproof/Fogproof Binoculars, Black 100% waterproof, O-ring sealed and nitrogen purged for reliable, fog-free performance Premium 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 10x magnification and 42mm objective diameter is ideal for long-range observations; 12-foot close focus distance; 17mm eye relief Features twist-up eyecups and a large center-focus knob for easy adjustments; limited lifetime warranty