B+W 67mm Circular Polarizer with Single Coating This filter uses our standard B+W F-Pro filter mount, which has a front accessory thread and is made of brass. Each glass surface is vacuum coated with one layer of Anti-Reflection coating. This single layer helps to prevent internal ghosting and reflections. It also improves light transmission from approximately 92% (uncoated glass) to over 98%. Manufactured from Water-White Schott Glass