The NIP-70-SGND0.9 is a graded filter for 70mm photo filter systems. This filter has a soft grade, which means the tint darkens very gradually from clear to dark. In this case, that tint changes goes from clear (0-Stop) to a 0.9 (3-Stop). The NIP-70-SGND0.9 has a standard thickness for a photo filter (2mm) and will work in any photo-standard filter system.