Welcome to the store! Durable to Use: The aluminum alloy shell is precision machined. Achromatic Lens: This 40X achromatic objective lens is designed for biological microscopes. Great Performance: Unwanted reflections can be eliminated and contrast can be increased. Clear Image: It provides high-quality observation without additional chromatic aberration. Easy to Use: The lens length is 37.8mm. Specifications: Item Type: Achromatic Objective Lens Material: Aluminum Alloy + Optical Lens Color: As Pictures Show Magnification: 40x Tube Length: 160mm/6.3in Conjugate Distance: 185 Shutter Thickness: 0.17mm Lens Length: 37.8mm Mounting Size: 20mm RMS Standard Thread) Item Size: 5×5×5cm/2.0×2.0×2.0in Package Weight: Approx. 62g Package List: 1 × Achromatic Lens Note: The data are all manual measurements, please allow 1-3cm error, due to the light and display difference, there will be a certain color difference, depending on the physical item received. Your satisfaction is our top priority. We will provide you with the best service. If you find any problems after receiving the product, such as damage, incorrect quantity, etc., please contact us immediately and we will give you the best solution!