Features 1、Small apertures of different diameters are provided in the optical system to meet different light transmission requirements. 2、Change the diameter of the aperture by the handle. 3、Metal material, reliable performance, durable. 4、We provides 5 kinds of aperture for you to choose from to meet different requirements. 5、Compact and practical design make the diaphragm works more stable. Specification Item Type:Iris Diaphragm SK25: Magnified Diameter: 1.5-25mm Material: Metal Outer Diameter :44mm Inner Diameter: 25mm Thickness :8mm 14 blades SK23 Outer Diameter: 37mm Minimum Aperture Diameter: ø1.5mm Maximum Aperture Diameter: ø23mm Material:Metal Thickness: 7.0mm 12 Blades SK12 Outer Diameter: 19.8mm Minimum Aperture: ø1mm Maximum Aperture: ø12mm Material: Metal Thickness: 5.0mm 10 Blades SK8 Outer Diameter: 14.8mm Minimum Aperture: ø0.8mm Maximum Aperture: ø8mm Material: Metal Thickness: 4.5mm 8 Blades SK6 Outer Diameter: 13.0mm Minimum Aperture: ø0.8mm Maximum Aperture: ø6mm Material: Metal Thickness: 6mm 8 Blades Package List 1 x Diaphragm