Overview: Highlight 2 types available (ND4, ND8) High quality optical glass for light reduction without affecting colortone Enable subject to stand out from background & capture naturalmoving object Prevent picture washout taken in outdoor sunny condition Increase contrast between sky & subject taken under bright sunnycondition Neutral Density filters are used primarily to reduce the amount of lightentering the lens without affecting the overall color tone. With lowerexposure value, pictures taken especially on waterfall will be morenaturalwith "flowing effect". Neutral Density 4 will reduce light volumeby 2 f/stops whereas Neutral Density 8 will reduce light volume by 3f/stops. Optics: Special ND colour optical glass Housing: Aluminum Mounting diameter: 37mm to 77mm Inner thread: Yes Specifications: Weight Approx:20g Size Approx:9 x 7 x 2