Grad FilterThe design of progressively lower close to the middle of the filter out allowing emphasis of foregrounds or backgrounds Color of lens regularly fades out, so the boundary between the colored and transparent sections of lens will not become obvious even with the lens aperture stopped down filter is mounted on rotating frame, so that you might be ready to rotate the coloring at any part of your image Giving your panorama and pores and skin texture a more colorful touch:Optical Resin