Pentax PF-80ED Spotting Scope with Field Case Eye Lens Cap - Objective Lens Cap - Case (70931) - Pentax Warranty The Pentax PF-80ED is housed in an 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.