A medium-edged line of transition from the clear area to the darkened density of 1.2, or a 4 stop light reduction Particularly useful for images that feature buildings, mountains and other elements that protrude into the skyline True to life color, No color cast High definition optical glass with NiSi Nano Coating on both sides - waterproof, anti-reflection, scratch resistant, and easy to clean Compatible with the NiSi 100mm System and any other systems that hold 100x150mm filters with 2mm thickness The 100x150mm Nano IR Medium Graduated Neutral Density filter from NiSi is specially designed for landscape photographers. This filter is made from high-quality optical glass (not resin) with nano coating to prevent losing any single bit of detail. The NiSi Medium GND Filter is a rectangular filter that helps to darken specific areas of an image, such as bright skies while allowing for a normal, unaffected exposure in the other regions of the image. The filter is densest at the edge and tapers to clear by the middle, with a medium-edged line of transition between the dense and clear areas. A neutral density filter with a medium-edged line of transition is particularly useful for images that feature buildings, mountains and other elements that protrude into the skyline. By using 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 added the infrared protection coating layer to this filter which helps to eliminate the infrared light through the lens to bring back the natural color. The NiSi 100mm filter system is great for cameras with lenses that have a standard filter thread from 49 mm to 95mm. This 100mmx100mm filter is compatible with the NiSi 100mm filter system.