The ZULU10 combines superior optical performance with in-the-field utility. High quality glass, fully multi-coated Spectracoat lenses, and phase-coated Abbe-Konig prisms provide maximum brightness, contrast and crisp resolution. The ZULU10 performs in the harshest conditions, giving unmatched performance in inclement weather or rugged terrain. ZULU10 barrels are nitrogen-filled and will not fog in cold, wet weather.Features :SIG SAUER'S HDX glass lenses pair high definition and high transmittance glass for ultrahigh resolution and light transmissionProprietary anti-reflective SpectraCoat, LensArmor, and LenShield technologiesUpdated locking diopter ring and 3 position adjustable eyecupsNewly redesigned focus wheel with an updated over mold provide ultra-fine focal adjustmentZULU10 HDX features a reinforced metal housing wrapped in rubber armor, offering durability with a sleek appearanceNew molded EVA carrying case for streamlined protection"Capable of being mounted to tripod adapter using a standard 1/4-20" threaded insert"IPX7 waterproof and fog-proof rated.