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, highly transparent optical glass that has been chemically enhanced and is four times stronger than regular protective glass. The HD coating consists of 16 layers on both sides, along with an anti-reflective multi-coating. Additionally, the filter is water and oil repellent, as well as scratch and dirt resistant. With its ultra-thin HD frame, the filter is compatible with wide-angle lenses. The frame has been mounted around the glass using a high-pressure pressing technique.