Usage Tips:view is also expanded, which is not only comfortable to watch, but also has a wider field of view and clearer imaging. Product Description: Magnification: 25X Field of View: 12mm Mounting Size (in diameter): 23.2mm Lens Material: Glass Shell: Metal Microscope: Biological Microscope Special reminder: This eyepiece is equipped with professional biological microscopes, with a diameter of 23.2mm. Not all microscopes can be used. Please do not buy this eyepiece if you use a toy microscope! (The diameter of the simple and toy microscopes on the market is 20mm or other sizes, which does not match this eyepiece) Please allow 0-2mm error due to manual measurement. Due to the difference between different monitors, the picture may not reflect the actual color of the item. Thank you! Material: Metal colour: black Package Contents: 1 x Biological Microscope Eyepiece Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.