Pentax PF-80ED 80mm ED Waterproof Spotting Scope - Angled - with 20-60x Zoom eyepiece & Case - Limited Lifetime USA Warranty Exceptionally lightweight magnesium-alloy body. Incorporating Extra-low Dispersion (ED) glass elements for optimum optical resolution. Large 80mm objective lenses for bright viewing under all light conditions. The receptacle has a special "O" ring assembly, which allows the body of the scope to be filled with nitrogen, making it fog proof and JIS Class 6 waterproof. A built-in lens shade cuts excessive light and helps to prevent rain and other weather elements from interfering with viewing.