Features: Brand new and high quality Reliable Materials: The apertures diaphragm is made of aluminum alloy and steel, strong and very reliable in performances. Wide Application: This adjustable apertures diaphragm is suitable for cameras, microscopes and other machines, which can help them work better. 1.5mm To 26mm Adjustable: The apertures has an outer diameter of 45mm and an adjustable inner diameter of 1.5mm to 26mm, which provides small holes with different in the optical system to meet different light transmission requirements. Simple Operation: Just use handle to change the apertures diaphragm diameter, which is easy to operate and more directly for adjustment. Highly Stable: This diaphragm is light weight, will not add weight for optical system, with good strength, rust and resistance, very stable. Specifications: Material: Aluminum Alloy + Steel Outside Diameter: approx.45mm/1.77in Color: Black Quantity: 1 Pc Package Includes: 1Pc Adjustable Apertures note: Please allow 0-1cm error due to manual measurement. please make sure you do not mind before you bid. Due to difference between different monitors, the picture may not reflect the actual color of the item.