Cokin p121m gradual grey g2 medium nd4 filter
Cokin graduated nd filters are just the ticket for landscapes where the sky is particularly bright and thus susceptible to being over exposed or when you want a darker moodier sky the filter retains normal colour balance across the visible spectrum with a progressive graduation from the middle to the top of the filter for those familiar with the cokin line the p121m filter has the same colour as the 121 filter but a lower tone