Graduated Neutral Density (ND) Filters allow you to reduce the amount of light reaching the sensor on a portion of your picture. This helps control the exposure difference between Highlights and Shadows for a more balanced exposure and dramatic effect. By rotating the filter-holder and adjusting the position of the filter up and down you can precisely control where the filter has an effect on the image.(Adaptor ring and filter-holder sold separately)Specs:- Density: 1-Stop Hard , 2-Stop Hard , 3-Stop Hard- Filter Dimensions: M (P) - 84mm x 100mm x 1.6mm, L (Z) - 100mm x 150mm x 1.6mm, XL (X) - 130mm x 170mm x 3mm- Filter Construction: C39 Optical ResinWhat's in the box:- Graduated ND2 Hard/121L (1 f-stop)- Graduated ND4 Hard/121M (2 f-stops)- Graduated ND8 Hard/121 (3 f-stops)- 3x Cases for filters