Pentax PF-100ED spotting scope has a large 100mm objective lens for bright viewing in all lighting conditions and utilizes the XL telescope eyepieces renowned for their sharpness, field of view, contrast, and freedom from aberration. The Extra Low Dispersion (ED) optics incorporate Lanthanum Crown (rare earth) glass elements for optimum resolution. The scope accepts all standard 1 ¼ inch interchangeable telescope eyepieces. It is waterproof, fogproof, and nitrogen filled. The Super-Multi-Coating maximizes light transmission, clarity, and contrast. The PF-100ED has a lightweight magnesium alloy housing, built-in lens shade, and includes field case..