The full nd kit from cokin contains a set of three nd filters p152 neutral grey nd2 03 p153 neutral grey nd4 06 and p154 neutral grey nd8 09 designed to reduce the amount of light reaching the sensor without affecting the colour balance these filters can be used alongside a long shutter speed to capture smooth motion in waterfalls and cloudy skies and allow you to play with backgrounds distance and depth of field the nd2 is equivalent to a 1 stop shutter speedaperture decrease