Feature:1. 4-60mm adjustable aperture to meet different light transmission requirements.2. Easy to install, adapt to a variety of optical instruments, cameras, etc.3. With 18 blades, it is easy to adjust and make the diaphragm work more stable.4. Selected highquality aluminum alloy materials, strong and durable to use.5. Exquisite processing and manufacturing, stable and reliable performance.Specification:Item Type: Lens DiaphragmMaterial: Aluminum AlloyModel: SK60Uses: Optical InstrumentsBasic Parameters:Inner Hole Size: Approx. 4-60mm / 0.2-2.4inOuter Circle Size: Approx. 82mm / 3.2inThickness Size: Approx. 8mm / 0.3inNumber of Blades: 18.Package List:1 x Lens DiaphragmNote:1. Please allow 0‑1 inch error due to manual measurement. Thanks for your understanding.2. Monitors are not calibrated same, item color displayed in photos may be showing slightly different from the real object. Please take the real one as standard.