The Cokin Hard-Edge Graduated Fluorescent Mauve 1 is a 2-stop filter that can be used to enhance dull, flat, or hazy skies. The filter is densest at the edge and graduates to clear at the middle, with a hard-edged line of transition. Hard-edge filters are great for images with a defined horizon line. The filter is rectangle so you can selectively choose where the tobacco edge sits in the framing of the image. | Cokin Z668 M1 - Graduated Fluorescent Mauve Filter - Hard Edge, 2-Stops, inZin