Designed to screw into a NiSi S6 150mm filter holder adapter ring Does not require adjustments to exposure while in use High definition optical glass with NiSi Nano Coating - waterproof, scratch resistant, and easy to clean The NiSi S6 PRO Circular IR ND8 (0.9) 3 Stop for S6 150mm Holder is designed for use with a NiSi S6 150mm filter holder system. It can screw into a NiSi S6 150mm filter holder adapter ring after the kit's included Pro Screw-In Circular Polarizer Filter has been removed. When in use, this ND provides a 3-stop exposure reduction. Its 0.9 density creates 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 are able to control depth of field and convey movement more easily. ND filters are also helpful when the contrast between the highlights and shadows is too high to get a quality exposure. The ND8 3 Stop is commonly used for waterfalls and capturing water flow at shutter speeds from 0.5 seconds to 2 seconds. NiSi ND filters do not affect the coloration of the image, offer a true to life color, and are made from high-quality optical glass (not resin) with nano coating to prevent losing any single bit of detail. By using a neutral density filter the camera is vulnerable to infrared light which will cast the unwanted red color to the photos when shooting at a small aperture. NiSi ND filters have an infrared protection coating layer to eliminate the infrared light through the lens to bring back the natural true to life color. Our proprietary NiSi Pro Nano Coating helps to reduce unwanted reflections and provides a waterproof and scratch-resistant layer to assist in the cleaning of unwanted fingerprints, dust, and water stains. Please note if using this with an older generation S5 adaptor, the S6 holder frame must be used in combination.