The Seascape Set is made from the following Lee Seven 5 filters: 1x 0.3 (1-stop) ND Hard Grad, 0.9 (3-stop) ND Hard Grad & Big Stopper (10-stop) ND filter. The Big Stopper reduces the amount of light reaching the sensor by 10 f/stops, which allows the use of slower shutter speeds. By increasing the length of exposure time you can create a ghostly, time-passing effect of anything that moves, for example the sea, clouds, waterfalls & people etc. Neutral Density Grads are designed to balance light intensity between two areas within a scene allowing better tonal range & detail. The darker half of the filter is often used to correctly expose the lighter part of the scene, such as the sky, while the bottom lighter half is used for the foreground. The Lee Seven 5 Seascape Set requires the Lee Seven 5 filter holder & Seven 5 adapter ring to fit your lens (not included, available separately).