Hoya 52mm DMC PRO1 Digital ND4X (0.6) Neutral Density Filter DMC: Digital Multi-Coated Filter. Greatly reduces the appearance of lens flare and ghosting caused by reflections BAF: Black Almite Frame. a black matte aluminum satin finish almite frame which reduces reflections BRG: Black Rimmed Glass. reduces the chance of light reflecting off the edge LPF: Low Profile Frame. Ultra Thin Frames to help avoid vignetting on super wide angle lenses. These frames are do hold a lens cap KEF: Knurling Edge Frame. These filters are equipped with a straight knurling edge for non-slip, easy attachement and removal