Oil and Water Repellent Coating: The Exus has a special Anti Foul coating, In rain or inclement conditions water will be repelled off the surface | The filter surface is also finger grease resistant. Extreme residue can easily be wiped off | Anti-Static Coating: Exus filters feature an Anti Static coating inhibiting adhesion of microscopic dust | Ultra Low Reflective Filter Mount: The Exus outer rim has a special black ink coating, The incidence of reflection is less than 0.3 Percent | The filter mount is ultra - thin for wide angle use and has light blocking ridges and a patented new glass securing system