The B + W 60mm XS-Pro Digital MRC Nano Kaeseman Circular Polarizing Filter is constructed from select polarizer foils and especially prepared optical glass. Kaeseman ("encased") filters are completely edge-sealed for maximum durability under extreme climatic conditions. XS-Pro filters are extra thin for use with ultra wide angle lenses, yet, they retain their front threads. B + W's MC Nano coating takes filter production to a new level. It features 7-layers of anti-reflection coating as well as improved cleaning capabilities. Water droplets will bead up better and be easier to remove from the filter. This filter is also scratch-resistant.