The B + W filters are made of brass alloy with excellent physical properties and high-purity, distortion-free, thick Schott glass, with a particularly precise design, state-of-the-art manufacturing technology and the highest quality standards. Finally, different types of surface treatment are provided to complete the perfection of B + W filters. From the raw materials used to the final touches, 100% "Made in Germany". B + W High Transmission Käsemann circular polarizing filters (factory code: AUC) radically reduce reflections and increase image saturation. The polarizing filter is an almost indispensable accessory for outdoor photography. To achieve optimal performance, the filter must be adjusted by turning the outer part. You can check the correct position in the search image. When used, the natural blue of the sky becomes visible, white clouds appear. By excluding the reflection of the water surface or glass surfaces, the contents behind them can also be photographed. High Transmission Polarizing Filters produce 1 light less light than other models. This is a huge advantage, a greater freedom factor for the photographer. Käsemann manufacturing technology means perfected quality in the production of polar filters. These filters are made of the highest quality polar foil, which is installed in a perfectly flat position between the glass sheets and then this "sandwich" is glued on the outside and matte painted into a uniform structure. Dirt and moisture can no longer get inside the filter, between the glass panes. This filter is equipped with eight layers of surface treatment (MRC) on both sides, which provide anti-reflection and dirt resistance, among other things. This filter is made with an F-pro socket, which is a standard B + W socket that is also great for use with wide-angle lenses. They are also equipped with a front thread, so that an additional filter (eg CPL) or accessory can be attached, as well as internal nail lens caps.