NiSi 77mm True Color ND-VARIO Pro Nano Filter with Hard-Shell Filter Case (Fits 8 Filters)NiSi 77mm True Color ND VARIO Pro Nano 1 5 Stops Variable ND Filter The NiSi True Color ND VARIO Pro Nano 1 5 Stops Variable ND is designed to mount onto lenses with 77mm front filter threads and provides an exposure reduction of 1 to 5 stops. The 0. 3 to 1. 5 density creates a darkening of the entire image, allowing wider apertures or slower shutter speeds than usually possible. The degree of density is easily controlled by rotating the front filter