Apochromatic aberration can simultaneously correct the three of color (red, green, and blue). The result not only realistically reproduces red, green, and blue, but also significantly improves the restoration ability of color intermediate colors. This type of lens often adopts an aspherical lens design, so it also corrects for spherical aberration (., focusing the same object image at different distances in different areas of the lens, resulting in a softer image). Apochromatic lenses have a complex structure and are made of special materials such as glass, which are expensive and difficult to process. They are commonly used in high-end lenses. Coating: Multilayer antireflective broadband coating Design: 2 sets of 4-piece Apochromatic design Interface: 2-inch interface (with 1.25 inch adapter) The sleeve has M48 threads inside and can be installed with a 2-inch M48 x 0.75 filter lens Colour:Black Material:Metal Package Contents: 1 x barlow lens Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is 1-3cm.