K&F Variable Filter ND2-400 (1 to 9 Stops)This 1 to 9 stop, Variable Fader ND2 ND400 Filter from K&F Concept is a filter providing an adjustable light reduction of 1 to 9 stops. It darkens the entire image evenly, allowing a photograph to be made with a wider aperture or slower shutter speed without overexposing your image. By slowing the exposure time or increasing the aperture, it is possible to control the depth of field and blur movement, creating a dynamic look for streams, waterfalls,