1、Provide small holes of different diameters in the optical system to meet different light transmission requirements. 2、The compact and practical structure makes the diaphragm work more stable, light in weight and easy to operate. 3、It is manufactured with high quality precise craftsmanship, with high quality, long service life, high strength and good durability. 4、The inner hole enlargement and reduction range is 1.5‑34mm, which can meet your needs and adapt to a variety of optical instruments, cameras, etc. 5、The material is made of aluminum alloy, which is not easy to rust, has good hardness, corrosion resistance, low density, reliable and durable. Item Type: Iris Aperture Material: Aluminum Alloy Color: As shown in the picture Model: SK34 Outer Diameter Size: Approx.49mm / 1.93in Inner Hole Size: Approx.1.5-34mm / 0.06-1.34in Thickness: Approx.5.6mm / 0.22in Application: Optical instruments such as lasering cameras 1 x Iris Aperture Note: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement.