Celestron's mid-size Outland Series was designed to meet the needs of every outdoor enthusiast, from birders and hunters to sports fans to travelers. The optics are multi-coated to obtain high resolution and high contrast views. The prism are made of BaK-4 glass to give you enhanced color fidelity.The rubber covered Outland X allows for rough and tough handling and the binoculars are waterproof and fogproof and are nitrogen purged for using in all weather environments. Large focus knobs make for easy and precise focusing and twist-up eyecups allow for quick adjustment of eye relief to obtain the full field of view.