BW Ksemann circular polarizers are manufactured with a polarizing foil of extremely strict & exacting specifications. In terms of color neutrality & extinction capability the foil quality is ideal. Furthermore the glass used for this filter is sanded & fine-polished for excellent optical quality & the advanced cementing technique prevents delamination in environments of high humidity. This filter does not impair the image sharpness of high-quality photographic lenses which is particularly important in high-resolution digital cameras & aspherical tele lenses. BW MRC nano Nanotechnology with Lotus Effect. Both sides of the BW MRC nano coated filters feature the same high-quality MC layer with 7 layers that is used in the MRC coating. This ensures high transmittance & maximum elimination of reflections by minimising reflection losses. Because the normal 4 reflection losses at the surface of the glass are reduced to an average of well below 0. 5 with an MC layer brighter colors & higher contrasts can be achieved. The MRC nano outer layer is an innovative extra layer that significantly outperforms the dirt- & water-repellent effect of the well-known BW MRC coating. Thanks to the nanotechnology-based surface property lotus effect dirt can hardly adhere. Water experiences a very efficient beading effect & virtually rolls off the surface of the glass. Cleaning the filter is incredibly easy & fast. In addition the superhydrophobic surface reduces fogging. After moving from cold to warm surroundings the condensation disappears from the surface of the filter glass within seconds. Why BW over other filter brands. BW filters have been made with Schott glass which guarantees the very highest glass quality. Good quality cameras & lenses are a major investment & at BW we believe that if you should have the best quality filters. Theres no point in buying an expensive optically superior lens only to put a piece of inferior glass over the front of it BW filters are