specification： Quality SAME LEVE OF Schott Optical Glass. 150*150mm, 5.9*5.9" Approx. 2.0mm thickness. It Could fit to Lee Filter"s SW150 Filter Holder. Features： ND filter darkens the image, allowing you to photograph with a longer shutter speed or wider aperture than normally required. Neutral Density filters do not affect the overall coloration of the image. Neutral Density filter evenly reduce the amount of light passing through the lens without effecting color. Ideal for reducing bright light in large aperture situations when a narrow depth is field is needed. Neutral Density Filters are often used to achieve motion blur effects with slow shutter speeds. High Quality Optical Glass 10 stop.Neutral .Density Filter ND 3.0 1000X. Increases control of depth of field. Eliminates overly bright, washed-out images. Balances exposures. Equally effective in color or black and white photography. Includes Filter Case. Made of optical glass same as Schott (same glass found in B&W & Heliopan filters).