The NiSi NIP-S5-ND1.8CPL is a round 6-stop dual neutral density filter and circular polarizer that screws into S5 filter holders in place of the native circular polarizer. This filter has a raised front lip for easy gripping when attaching or removing the filter, and can fit into the front slot of the S5 Filter Holder Case for convenient storage, or else can be stored in the included protective nylon sleeve.