DHG Multi-coated CPL. Pro quality filter. Ultra-low reflective coating minimizes reflection off internal CCD & CMOS sensors. Multicoated optical glass filter. Black rim: Edge treated with black ink to eliminate reflections. Low profile: Just 5mm high (not inc rear threads). Great for Wide angle lenses, no vignetting. Non-reflective metal frame eliminates reflections. Metal, double threaded frame to allow additional filters or hoods. A Circular Polarizer (polariser) creates contrast between blue sky and cloud for dramatic deep blue skies. Cuts glare off reflected surfaces such as water. Rotates for different effects.