Features: Brand new and high quality The maximum aperture of the iris diaphragm can reach 26mm, and the light transmittance is strongers, which can make the observed object clearer and brighter in the dark without receiving external light sources. Compared with using a small hole to pass through the aperture, the convenience of use is greatly improved. The adjustable aperture is 1.5mm-26mm, and the dynamic adjustment ranges is wide. A single original can be used in multiple scenes, and it get rid of the burden of needing multiple sets of apertures due to inappropriate apertures, making it more convenient to use. The outer casing of the microscope aperture is made of metal material, which is stable in structure and durable, protects the internal structure from damage, and greatly improves the service life. The compacts and practical design makes the diaphragm work more stably. The aperture of this microscope can be changed through the handle, which is easy to operate, compacts and easy to carry, and is a very practical laboratory accessory. Specifications: Material:Metal Color:Black Min-Diameter: 1.5mm Max-Diameter: 26mm Dia:Approx.37mm/1.45inches Note: 1.Please allow 1-2cm errors due to manual measurement, make sure that you do not mind before you order. 2.Due to the difference between different monitors, the picture may not reflect the actual color of the item. Package includes: 1x Lens Adapter Rings