The B+W 39mm XS-Pro UV Haze MRC-Nano 010M Filter is a general-use, clear filter designed to absorb ultraviolet light and reduce the bluish cast of daylight. Aside from the reduction of unwanted blue casts, no additional coloration or contrast is created, and adjustments to exposure are not required while using this filter. This Multi-Resistant Coating (MRC) also offers greater protection to the filter substrate and helps it to stay clean for longer than with uncoated filters. The Nano coating associated with XS-Pro filters provides an additional eighth layer over the MRC, resulting in an improved beading effect when in contact with water for greater cleaning efficiency. To further reduce the possibility of vignetting when this filter is in use, the filter ring's outside diameter is slightly larger than the actual thread size. This may prevent the use of some lens manufacturer bayonet hoods. Such filters help to reduce dust and moisture from reaching your front lens element and provide additional protection in case of drops or situations where scratching could occur. Nano coating provides an improved beading effect with water for more efficient cleaning. A thin brass filter ring helps to prevent vignetting, and jamming and provides additional strength.