SkyMaster Pro binoculars are the ideal choice for amateur astronomers or anyone that observes at great distances. Compared to lower-priced large aperture binoculars, SkyMaster Pro uses superior optics, coatings, internal parts and housing materials. With large objective lenses, BaK-4 prisms and fully multi-coated optics utilizing Celestron's proprietary XLT coating technology, the view through a SkyMaster Pro is second to none at this price point. Choose SkyMaster Pro for use at dusk, dawn and nighttime astronomical viewing. Fully Multi-Coated Optics and BaK-4 Prisms - Every air-to-glass surface is multi-coated with Celestron's proprietary XLT coating technology. These coatings coupled with BaK-4 prisms increase light transmission through the optical path and deliver crisp, high contrast images with outstanding resolution. When properly aligned with the binocular, the red-dot finder will allow objects to be brought into view quickly. The fully waterproof housing for use in all weather conditions provides peace of mind when unexpected weather rolls in. The housing is also filled with dry nitrogen gas to prevent the internal lenses from fogging when moving between extreme temperatures or when using the binocular in damp conditions.