B+W 82mm Slim-Line Kaesemann Circular Polarizer with Multi-Resistant Coating This filter uses our Slim-Line mount made of brass for wide angle lenses. They do not have a front accessory thread to avoid vignetting with lenses as wide as 17mm in 35mm format. A slip on cap is supplied with Slim filters, sizes 49mm through 82mm. MRC by B+W is not only an extraordinarily effective multiple layer coating, it is also harder than glass, so that it protects filters from scratches, and it is also water and dirt repellent, thus facilitating filter maintenance. Manufactured from Water-White Schott Glass