DESC: If youre looking for an affordable way to achieve high-power viewing of the moon and planets, double stars, and even close-up views of terrestrial subjects, a Barlow lens is the answer. The Ultima Series Barlow (2x by 1.25 inches) is an air-spaced, three-element apochromatic design with a 27mm clear aperture. This lens features a very high-quality, fully multicoated design. Amazingly compact and lightweight, its just 5 ounces and 2.75 inches in length.