This is a brand new 2X Barlow (auxiliary objective) lens for stereo/industrial microscopes. Give your microscope a boost with greater power & clarity at a fraction of cost. It doubles the magnification power of the microscopes This lens comes with a 1-7/8" (48mm) mounting thread and goes with VS-1F/VS-2F/VS-3F/VS-5F/VS-7F/VS-8F/VS-9F series stereo/industrial microscopes.