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 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 glass is 4x stronger chemically enhanced optical glass. Designed to protect a camera's expensive lens system from scratches and impact, HD nano 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 coating has superior water and oil repellent abilities that will make filter maintenance easy and stress free. KEY FEATURES ULTRA-HARD NANO COATING New 32 layer (both sides) ultra-smooth, ultra-hard nano coating Stain resistant, water & oil repellent coating makes everyday maintenance easier Ultra-hard surface coating is 800% more scratch resistant than general coating HD GLASS High Density Sharp Cut UV glass Chemically Enhanced Optical Glass is 4x Stronger than usual optical glass HD FRAME Very Thin Frame, Front thread to attach lens caps and other filters Press mount technology holds glass securely The HD nano filter that not only the hardened glass but also the ultra-hard nano coating protects your lens solidly under the severe conditions.