Welcome to our store! 1. The aluminum alloy shell is precision-machined, stable, and durable for long-term use. 2. This is a 4X achromatic objective lens for a biological microscope. 3. It can eliminate unwanted reflections and increase contrast. 4. Offers high-quality observation without additional chromatic aberration, making the image clearer. 5. The objective lens length is 30.5mm, easy to use. Features: 1. Precision-machined aluminum alloy shell for long-lasting durability. 2. 4X achromatic objective lens for biological microscopes. 3. Eliminates unwanted reflections and enhances contrast. 4. High-quality observation with no chromatic aberration for clearer images. 5. 30.5mm objective lens length for easy use. Specification: Item Type: Achromatic Objective Lens Material: Aluminum Alloy + Optical Lens Color: As Pictures Show Magnification: 4X Tube Length: 160mm / 6.3in 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 * 2.0in Package Weight: Approx. 41g Package List: 1 * Achromatic Objective Lens Customer Satisfaction - Customers are our top priority. If you find any problems with the product after receiving it, such as damage and incorrect quantity, please contact us immediately. We will do our best to provide you with satisfactory customer service.