This economy Celestron Barlow triples (3x) the power of any telescope eyepiece it is used with. Now you can give your telescope the power boost it needs for high power viewing! A Barlow lens effectively doubles the number of eyepieces in your collection!Works with most telescopes that have a 1.25" focuser. If you have a Newtonian reflector with a short focal length (fast) you will need a short Barlow. We have a short 3x Celestron Barlow listed in our eBay store. Comes with dust caps for the top and bottom. Length is 5".