DESC: The SkyMaster Series of large aperture binoculars from Celestron offer phenomenal performance for astronomical viewing. They are also a great choice for terrestrial use, especially over long distances. All models feature high quality BAK-4 prisms and have multi-coatings for enhanced contrast. The 80 and 100mm models are waterproof and feature structural reinforcement of the main body for maximum stability and secure optical alighnment- in addition, they have a built-in rigid photo tripod adapter.