This 4 x 5.65" Cine ND Filter from SmallRig is an ND0.6 neutral density filter that produces a 2 f-stop exposure reduction, making it possible to reduce shutter speed for added blur when shooting still images, or for finer control over frame rate when shooting video. In addition, shooting at a wider aperture to reduce depth of field helps isolate the image subject from the background. This filter is compatible with any 4 x 5.65" matte box or filter holder that has a filter slot for 4mm-thick filters.