Amazon.com : 3X Barlow Lens, 3X Astronomical Telescope Eyepieces Barlow Lens with M42x0.75mm Thread, T Ring Adapter for 24.5mm Astronomical Telescope/Digital Camera : Electronics
Tebru 3x Barlow Lens M42x0.75 Thread Interface for 1.25 Inch Astronomical Telescope Eyepieces, 3X Lens, 3X Barlow Lens - Walmart.com