Feature: 1. Block Wavelength: Light pollution reduction filter blocks the wavelength of light from common light pollution sources, allowing the picture to show true colors and high definition picture quality. 2. Optical Glass and CNC Precise Molding: Optical glass, no color cast, to ensure high definition image quality. CNC precise molding, non slip pattern, thin gold thread design. 3. Double Sided Multi Layer Coating: The light pollution reduction filter is waterproof, oil proof and scratch resistant to protect your camera lens. 4. Ultra Thin Frame Design: The ultra thin frame minimizes vignetting from wide angle and telephoto lenses. 5. Applicable Scenes: Natural night filter light pollution filter is great for nightscapes and astrophotography. Specification: Item Type: Light Pollution Reduction Filter Material: ​Optical Glass, Aluminum Alloy Number of Coating Layers: Double Sided 18 Layer Coating Frame Thickness: Approx. 3.15mm / 0.1in Color: As Pictures Shown . Package List: 1 x Filter1 x Filter Box