BUSHNELL 134218 H2O WATERPROOF FOGPROOF PORRO PRISM BINOCULAR, 8 X 42 MM, BLACKFeatures: BaK-4 prisms for bright, clear, crisp viewing Multi-coated optics for superior light transmission 100% waterproof: O-ring sealed and nitrogen purged for reliable, fog-free performance Non-slip rubber armor absorbs shock while providing a firm grip Twist-up eyecups Large center-focus knob for easy adjustments Longer eye relief Porro Prism System*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