IMPROVED PROTECTION PERFORMANCE AND DURABILITY The coating of the filter is not permanent. It gets a damage repeatedly when we clean it with wipes and gets weak as time passes by. The filter can protect the lens from physical damage, but the coating receives the strike first as scratch. When a coating of a filter is solid and scratch resistant, it will be a great advantage. This is designed with ultra-hard nano coating to protect your camera lens. The HD nano Mk II UV filter is a filter with a UV cut curve that does not affect the visible light range. In addition this filter features a new powered coating that protects the lens from scouring, while allowing easy cleaning of water spots and fingerprints. The HD nano Mk II glass is 4x stronger chemically enhanced optical glass. Designed to protect a camera's expensive lens system from scratches and impact, HD nano Mk II filter is essential gear for photography under extremely severe conditions. POWERED COATING Newly developed coating is stuck to the glass surface more firmly and closely by the nano level than formerly. Due to this, the particles are layered on the glass surface with extremely high density that creates a hard and smooth coating. Besides ultra-hard and smooth features, HOYA HD nano Mk II coating has superior water and oil repellent abilities that will make filter maintenance easy and stress free. HARDENED GLASS Hardened optical glass that has 4 times the breaking strength.