Amazon.com : Barlow Lens 2X, Bysameyee 1.25 Inch Fully Multi-Coated Metal Barlow Lens with M42 Thread Camera Connect Interface for Telescope Eyepiece : Electronics
Amazon.com : Celestron 93230 8 to 24mm 1.25 Zoom Eyepiece & Omni 2X Barlow Lens : Electronics
Celestron Omni 2x Barlow Eyepiece By Magnification Eyepiece Professional Telescope Barlow Parts Astronomical Eyepiece
Celestron 1.25" Omni 2x Barlow Lens Achromatic By Magnification Eyepiece Professional Astronomical Telescope Eyepiece Parts - Telescope - AliExpress