Features: 2X Barlow lens, 23.2mm mount interface. Fully multi-coated optical lens, providing you high-defination clear view. Lens body is full black metal constructed and precisely CNC-machined, durable for long for time use. Suitable for biological microscope. Operation method, place it between the eyepiece tube and the eyepiece, easy to use. Specifications: Magnification: 2X Body Material: Metal-Aluminum Alloy Lens Material: Optical Glass Lens Coating: Full Multi-Coated Interface Size: 23.2mm Colour: Black Volumw: Approx. 69x27x27 mm/2.71x1.06x1.06 inch Package Includes: 1 Piece 2X Barlow Lens note: Please allow 1-2cm errors due to manual measurement,pls make sure that you do not mind before you order. Due to the difference between different monitors, the picture may not reflect the actual color of the item.