HD nano Mk II coatings are the toughest, most scratch and dirt resistant coatings offered by any manufacturer. The ultra hard nano coating is designed to protect your lens. The HD nano Mk II UV filter is a filter with a UV blocking curve that does not affect the visible light range. In addition, this filter has an active coating that protects the lens from rubbing while allowing for easy cleaning of water spots and fingerprints. The HD nano Mk II glass is a 4x stronger, chemically enhanced optical glass. Designed to protect a camera's lenses from scratches and bumps, the HD nano Mk II filter is an essential accessory for photography in extremely challenging conditions. The developed coating adheres to the glass surface more tightly 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 that make filter maintenance easy and stress-free.