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.Adding a full ND filter allows you to reduce the exposure over the whole image. This helps you reduce shutter speeds to create blurred motion effects in water and clouds as an example.This item is available in 2 sizes:M (P) Series: 52mm, 55mm, 58mm, & 62mm Adaptor ring, orL (Z-PRO) Series: 67mm, 72mm, 77mm, & 82mm Adaptor ring.Specs:- Density: 2-Stop Hard, 3-stop Hard, 2-Stop Full- Graduation Type: N/A- Filter Dimensions: M (P) - 84mm x 100mm x 1.6mm, L (Z) - 100mm x 150mm x 1.6mm, Note - Full stop filter is square- Filter : GND4/121M, GND8/121, ND4/153What's in the box:- Cokin Filter Holder- 4 Cokin Adapter ringsM (P) Series Option: 52mm, 55mm, 58mm, & 62mm Adaptor ring, orL (Z-PRO) Series Option: 67mm, 72mm, 77mm, & 82mm Adaptor ring- Graduated ND4/121M Hard (2 f-stop)- Graduated ND8/121 Hard (3 f-stops)- Full ND4/153 (2 f-stops)- Microfiber Cleaning Cloth