A Protector Filter is a popular addition to camera equipment as it protects the front element of the lens from scratches, dirt, water and other foreign objects. It can also make cleaning the lens easier, as you can simply remove the filter and clean it instead of the lens. The Hoya HD Protector Filter features Ultra Clear High Transparency Optical Glass, which is chemically enhanced and 4x stronger than regularly used protective glass. The HD coating consists of 16 layers on both sides, as well as an anti-reflective multi-coating. In addition, the filter is water and oil repellent, scratch and dirt resistant. The ultra-thin HD frame makes the filter more wide-angle lens compatible. The frame was mounted around the glass using a high-pressure molding technique.