From the Manufacturer: These premium binoculars of the BRESSER Pirsch series is the ideal model for vacations, travelling or while hiking amongst other activities. The high quality binoculars have the newest phase coating that allows the picture shine more clear in contrast and high-definition, reinforced by fully-multicoated lenses.The BaK-4 glass material provides a bright and clear picture. TwistUp eyecups enable spectacle wearers to also enjoy the full field of view, they are adjustable in 2 steps and also support the view without glasses. The BRESSER Pirsch Binoculars have a rubber armored body for solid grip. All Pirsch models come with a broad and very comfortable neckstrap. To complete the package these binoculars are waterproof and nitrogen purged to prevent them against fogging.