Features Optical lens: The 4X achromatic objective lens of the biological microscope is 100% brand new. It adopts optical lens, which is highly professional and has a conjugate distance of 185. Aluminum alloy shell: The shell of the microscope achromatic objectives lens is made of aluminum alloy precision processing, stable performance, not easy to corrode, solid material, and can be used for a long time. Size: The length of the microscope achromatic objectives lens is about 160 mm / 6.3 inches, the installation size is about 20 mm / 0.79 in (standard RMS thread), and the packaging weight is about 41 grams. 30.5mm/1.2inch objective lens: The length of the objective lens is about 30.5mm/1.2inch, which is easy to use. The thickness of the cover glass is about 0.17 mm / 0.007 inch, which is strong and not fragile Eliminate unwanted reflections: The microscope objective lens can eliminate unwanted reflections and increase contrast, providing high-quality observation without additional chromatic aberration, making the image clearer. Features: 1. Aluminum Alloy shell is precision machined, stable and durable for long time use. 2. This is a 4X achromatic objective lens for biological microscope. 3. 4X achromatic objective lens can eliminate unwanted reflections and increase contrast. 4. The microscope objective lens offers high quality observation without additional chromatic aberration, make image more clear. 5. The Length of the objective lens is 30.5mm, easy to use. Specification: Item Type: Achromatic Objectives Lens Material: Aluminum Alloy + Optical Lens Color: As Pictures Show Magnification: 4X Tube Length: 160mm / 6.3inch Conjugate Distance: 185 Cover-glass Thickness: 0.17mm Objective Lens Length: 30.5mm Mounting Size: 20mm（Standard RMS Thread) Item Size: 5 * 5 * 5cm / 2.0 * 2.0 * 2.0inch Package Weight: Approx. 41g Package List: 1 * Achromatic Objectives Lens Package List