ED Glass: The spotting scope incorporates Extra-low Dispersion (ED) glass elements in its optical design. Straight Viewing Design: The PF-80ED spotting scope features a straight-through viewing design, which makes it easier to quickly locate and track moving subjects. 80mm Objective Lens: The PF-80ED features a large 80mm diameter objective lens, which gathers ample light to provide bright and clear images, even in low-light conditions.