Double your pleasure! Celestron"s Omni, 1.25-inch, 2X Barlow lens is on everyone"s list of absolute must-have accessories. A very good entry-priced Barlow, it will make quite a difference in your telescope"s performance. The Barlow lens doubles the magnifying power of any eyepiece it"s used with. For example, an 18mm eyepiece used with a 2X Barlow lens would have the magnifying power of a 9mm eyepiece. And on a telescope with, say, 1,500mm focal length, magnification would jump from 83X without the Barlow to 166X with it. It"s like having two eyepieces in one! No wonder folks like them: they can instantly double their eyepiece collection. * 2x Barlow Lens that doubles magnification * 1.25 inch format design * For use with all 1.25 inch eyepieces * Low profile, 2-element design * Fully-Multicoated optical design with blacked lens edges