B+W 77mm XS-Pro Digital Vario ND with Multi-Resistant Nano Coating Neutral Density Variable Filter allows photographer to set the density between +1 and +5 stops. XS-Pro Vario ND mount is an extra-wide design and should avoid vignetting concerns with most 17mm lenses on a full body frame. Multi-Resistant Coating (MRC) with Nano Technology with XS-Pro mount and brass ring construction May be combined with additional B+W ND Filters of fixed value for higher density choices (ND Vario should be used the as the outermost filter when combined) B+W ND Vario filter can be adapted to your individual requirements