Haida 52mm CPL Filter Slim PROII Multi-Coated Circular Polarizer C-POL MC HD2021-52 High Quality Optical Glass Multicoated Circular Polarizer Filter Reduces glare in water and reflective surfaces, great for foliage in making leaves less shiny Enhances Colors, Darken Blue Skies turning them into deep rich blues Protects your camera lens from dust, moisture, scratches and fingerprints Double threaded to stack additional filters such as: ND, UV, etc.