Made from the ultimate optical resolution and strongest Toughened Corning Gorilla Glass IIINeutral Density filter with Central section of exposure reduction, this is especially useful where the subject shows a very bright mid-section. This filter is used to control reduce exposure in the upper area of the image, with a gradual light transmission fall off. This filter type is often used in conjunction with a soft GND for control over the upper part of the exposure area.Oil/water-proof & double-sided coatingsRated best filter system of 15 brands by On Landscape Magazine May 2019Pre-fitted with Patented H&Y Magnetic Filter Frame, these filters can only be used with 100mm K-Series Filter Holder or adapted 3rd party holders using H&Y Magnetic Filter Adapter kits