1.25 Inch 3X Barlow Lens for Newtonian Telescopes Eyepiece Essentially triples the power of any 1.25" telescope eyepiece with the universal Barlow Lens Compatible with most 1.25-Inch diameter telescope eyepieces and other accessories Includes both end caps to protect against dust and fingerprints; This Barlow comes with a set screw to securely hold your eyepieces works on Celestron, Orion , and most brands of telescope. Works great for the price.