Adjustable Iris Aperture Diaphragm Microscope Iris Adapter Aperture Adjustable Lens Optical Diaphragm for Microscope Iris Diaphragm<br> Small apertures of different diameters are provided in the optical system to meet different light transmission requirements.<br> Change the diameter of the aperture by the handle.<br> Metal material, reliable performance, durable.<br> Compact and practical design make the diaphragm works more stable.<br> Colour: Black<br> Size: inner diameter 12mm, outer circle 19.8mm<br> Quantity: 1pc<br> Kind tips:<br> 1.As different measuring methods,it will occur 1-3 cm deviation about the items,please ensure that it is okay for you before ordering.<br> 2. Because of different monitors and lamplight, the picture may not reflect the actual color of the item, really thank you for your kind understanding.<br> 3. Only the above package contents, excluding other products.<br>