1.0X 2.0X 0.3X 0.5X 0.7X auxiliary barlow objective lens for Binocular/Trinocular Microscope. WD165 0.5X 0.7X 0.3X 1.0X 2.0X auxiliary objective lens zoom stereo microscope barlow lens for Stereo Microscope. Features: - Magnification Power, Doubling Total Magnification power of your Microscope and reduce the focus length. - This lens comes with a 1-7/8" (48mm) mounting thread and goes with stereo microscopes. - Mounting size: 1-7/8" (48mm) in diameter. - 0.5X Barlow lens doubles working distance and field view of stereo microscopes, cutting magnification power by half and doubling working distance and field view of the microscopes.