Rodenstock 88030 HR 77mm CPL Circular Polarizer MC Digital Filter Stringent quality precision machined crafted metal rings to ensure optical flatness Professional thin design filters for all imaging applications for both wide angle and telephoto lenses Designed for use with high preformance optics Meets RoHs standards for enviromental concerns A unique quality scratch resistant lotus leaf hardcoat to prevent abrasions and the effects of moisture while providing a professional standard of light transmission necessary for high resolution imaging