SVBONY 1.25" 31.7mm Barlow Lens 3x Apochromatic Three-element APO Design Plastic for Astronomical Telescope Eyepieces Astronomy Spotting Scope The value 3x barlow lens dobule times magnify of any 1.25" eyepiece;double the capacity of an existing set eyepieces at the cost of a single eyepiece 3 element APO design:fully multi coated optics provide high power magnification and sharp views;allow you look more closely and more detailed at the moon's surface and other planet The SVBONY 3x barlow lens works on any brand telescope that use with 1.25" telescope eyepiece filters;with safety undercut and brass compression ring;so the eyepiece are not marred by captive set screw Includes both end caps to protect against dust and fingerprints;this barlow comes with a set screw to securely hold your eyepieces;main material is plastic;but it works well Lifetime warranty;we confidently promise lifetime warranty for each one from us