The Cokin W951 X-Pro Filter Kit contains a Cokin X-Pro filter holder plus an X series 121M Graduated Grey ND filter & a 164 Circular Polarising filter. The X121M Graduated Grey ND filter means that you can balance light intensity, such as in bright contrasty landscapes where exposing for the foreground will produce a washed-out sky, while exposing for the sky will leave the foreground dark. Cokin grad ND filters are part clear, part neutral density & allow the transition to be blended into the scene. The 121M is a 2 stop ND grad that will compensate the average bright sky-to-foreground situation & is the most popular density of the series. The X164 Circular Polarising filter can remove unwanted reflections from non-metallic surfaces such as water or glass & also saturate colours providing better contrast. The effect can be seen through the viewfinder & changed by rotating the filter. Circular polarisers are specifically designed for use with auto-focus SLR cameras but will also work on manual systems.