The NiSi Switch 100mm Filter Holder allows two filters to be rotated together or independently from each other. It's designed for the photographers who need graduated ND filters positioned at different angles plus allows them to rotate independently and smoothly. The Switch allows smooth 360 degrees rotation but also has a locking screw to fix the back holder in position. The holder has no vignetting even at 16mm on a full-frame and is well suited for complex lighting situations.The switch is compatible with filters 100mm wide and 2mm thick.The NiSi Switch is a filter holder that works with the 82mm main adapter included in the following NiSi kits: V6/V5PRO/V5. (If you are an existing NiSi user you can just order the Switch as an additional filter holder to add to your kit).Please note: The NiSi Switch 100mm Filter Holder requires the NiSi 82mm adaptor ring for the 100mm system to mount to a lens and does not include any filters.???