These filters allow the user complete creative control over your subject. Each filter can rotate to provide the user with control over the color placement against the subject. The gradual color transition delivers a smooth blending effect, adding a natural flow to the image & the double threaded front allows multiple filters to mount on each other. By compounding two color graduated filters, each rotated 180 degrees relative to the other, creates a two-tone effect. These filters are constructed of high-quality metal and Japanese Optics.