The Haida M10 Drop-In Nano-Coating Filters feature High Quality K9 Optical Glass The glass comes with anti-reflection, scratch-resistant, waterproof coatings on both sides of filter. Stops from 1 to 12 are available. Darkens Entire Image, Greater Control Over Exposure Settings The Haida filters create a darkening of the entire image, allowing you to photograph with a wider aperture or slower shutter speed than normally required. By slowing your exposure time or increasing your aperture, you can control depth of field and convey movement more easily. Neutral density filters do not affect the coloration of the image and are ideal for pairing with other filters. This neutral density filter is mounted within a drop-in assembly that is made specifically to fit between a separately available Haida M10 Filter Holder and an adapter ring for the filter holder. These filters are constructed from optical glass for clarity and color fidelity. To prevent internal ghosting and reflections, each glass surface includes 10 layers of anti-reflection coatings, which also offer greater protection to the filter substrate and help keep it clean for a longer period of time. The Nano coating associated with this Haida Drop-In Neutral Density Filter provides an additional layer that results in an improved beading effect when the surface comes in contact with water or oil, allowing for more efficient cleaning.