With regular filters, a coating is not durable because it is repeatedly damaged by cleaning with wipes, for example, and thus becomes weak over time. For this reason, Hoya has developed a special ultra-hard nano-coating. The chemically strengthened optical glass is 4x stronger than commonly used protective glass and has a UV cut curve that does not affect the visible light range. Designed to protect a camera's expensive lens system from scratches and impacts, the HD Nano Filter is essential equipment for photography in extreme conditions. The newly developed nanoscale coating adheres to the glass surface more firmly and tightly than before. This layers the particles with extremely high density on the glass surface, creating a hard and smooth coating.