The NiSi Cinema V-ND Variable Viewing Filter (1 to 6 Stops) is a variable viewing filter from 1 to 6 stops. When you?re setting or focusing your lights it?s helpful to be able to stand in the spot where you want the light to hit, and look up directly into it as it?s being focused. NiSi have made an up to date version of the tool that uses a variable ND filter.