This S6 150mm Filter Holder from NiSi features two filter slots for the convenient use of up to two 150mm wide, 2mm thick square or rectangular filters. Each slot is designed to grip an installed filter only along the surface of the filter's edges, so contact with a filter's front or rear-facing surfaces is avoided. Positioning filters is particularly important when using 170mm-long graduated filters whose effect can be adjusted to better suit changing lighting conditions or creative demands by sliding them up or down within a filter slot. The S6 system allows the filter holder to rotate, and it has a lock to hold it in position. The filter holder supports the use of a rotating circular CPL.