About this item Principle ： The Haida C-POL Filter helps to reduce reflections and glare by filtering out light that has become polarized due to reflection from a non-metallic surface. A polarizing filter arranges and filters this directionally polarized light perpendicularly to the reflected light, allowing for the absorption of much of light. This increase in the saturation of skies and foliage. Material ：This filter is constructed from optical glass for clarity as well as color fidelity and features an aluminum-alloy filter ring that can be rotated in order to adjust the intensity of the polarization effect. Coating ：To prevent internal ghosting and reflections, the glass includes layers of anti-reflection coating. These coatings also offer greater protection to the filter substrate and helps it to stay clean for longer than with uncoated filters. Effect ：Circular polarizers are ideal for use with digital cameras and autofocus lenses，Clears up haze in distant landscapes and provides more saturated, vivid colors.Strongest effect when used at a 90° angle from the sun. Other ：Top knurling to provide a more textured grip when mounting or removing it from a lens，If you have any questions about Haida products, you can contact us at any time.