Model 4565081EFN9. 4x5.650 / 4x5.65 size for use with matte box. This 4 x 5.65" Tiffen Combination 81EF/ND Filter blends both an amber light-balancing 81EF and a 0.9 neutral density filter. The ND filtration provides a 3-stop exposure reduction for darkening the entire image in order to photograph with a wider aperture or slower shutter speed than normally required.