The Lee .9ND Graduated Neutral Density Hard Edge 4x6 Inch Resin-Requires Holder is specially capture the perfect images of horizons or any other hard transitions. While it is designed to be attached with the holder, this hard grad filter can also be used with other filters for optimized performance. It helps in capturing the perfect images without affecting the color balance. Moreover, it effectively controls the exposure selectively across the frame. This filter comes with the strength of .9ND that is equal to the reduction of exposure by 3 stops.