Alpen Shasta Ridge 8.5x50 Waterproof Roof Prism Binocular is fully multicoated, maintains eye relief and features BAK4 optics. This allows hunters, shooters, bird watchers, boaters and outdoor enthusiasts with precision viewing under all conditions. The full size models of Alpen Binoculars have a sleek roof rism design while the compact models are porro prism design. Both designs provide the performance required by the most dedicated sorts optics users. Shasta Ridge Binoculars meet the extreme weather needs of today's active adventurers.