HD nano Mk II coatings are the toughest, most scratch and stain resistant coatings offered by any manufacturer. The HD nano Mk II coating is 200% harder for longer life and better protection. The highly transparent polarizing film has 25% better light transmission than the standard polarizing film used in current photographic filters. This means that nearly half a stop more light enters the lens while achieving the same polarizing effect, maintaining the color balance of a standard circular polarizer while improving contrast and clarity. With the HOYA HD nano Mk II CIR-PL filter, you can create unique effects in your photo that are not possible with post-processing software. The newly developed coating adheres to the glass surface more firmly and densely than before due to the nano level. As a result, the particles are layered on the glass surface with extremely high density, resulting in a hard and smooth coating. In addition to the ultra-hard and smooth properties, the HOYA HD nano Mk II coating has excellent water and oil repellent properties, making filter maintenance easy and stress-free.