The fader ND filter is a variable neutral density filter. By rotating the ring, it offers 2 to 8 stops added density. A prefer tool to produce slow shutter effects or large aperture with a result of beautifyl broken under strong light. Neutral Density (ND) filters can reduce the intensity of light without appreciably changing its color. Classic ND filters have different f-stop reduction numbers and transmittance thus generated can be applied for different shooting conditions, such as portraiture, water falls, fountain etc. Easier to control Flash output . No need to carry a bunch of Filters for shooting. One filter gives you the range from ND2 to ND400 Bigger front thread size can reduce the dark angle. Specification: Fotga ND fader filter is a compact all-in-one variable neutral density fader filter that adjusts the amount of light reduction with just the twist of your wrist. The index marks on the filter let you know exactly the amount of reduction at a glance. Giving you clear and precise shots at whichever density you are using. It is able to adjust neutral density freely from ND2 to ND400. It offers you the freedom the create different neutral density freely. Type: FOTGA Fader ND Fliter Material: Optical Glass Color: Black Rotating: Yes Neutral Density Grade: 2 - 400 Package Includes: 1x Fotga slim fader ND filter