Vanguard's Endeavor ED II binoculars feature Extra-low Dispersion (ED) glass and phase-corrected BaK4 prisms that work together to virtually eliminate chromatic aberration, which produces images with true color fidelity across the entire field of view and enhanced contrast. Complementing the glass and prisms are anti-reflection, fully multi-coated optics that improve light transmission for bright and clear images, with greater low-light performance. An open-bridge design helps to reduce weight without sacrificing strength, and provides a large surface area to hold. Pebbled rubber armoring helps to give protection from drops and impacts while helping to provide a non-slip grip. Designed for durability, the lightweight magnesium-alloy housing is nitrogen-filled and o-ring sealed for water and fogproof performance, and the 3-stage click-stop twist-up eyecups provide a custom fit eye relief for use with or without eyewear.