0.3X Barlow Auxiliary Objective Glass Lens For XDC-10A 180X 300X C-MOUNT Lens Industry Video Microscope Camera Feature:0.3X Magnification Powerfor Industrial Microscope Camera C-MOUNT Lens1-3/4" (42mm) Mounting ThreadDoubling Total Magnification power of your Microscope and reduce the focus lengthObjective Magnification Power by 0.7 - 4.5X