The Cokin P1215 filter has a progressive graduation from the middle to the top of the filter, with the same colour as tone the 121 filter.
Cokin Z121M Neutral Grey Gradual ND4 Filter
AyuGlo Gradual Tan
Cokin P-Series (M) NUANCES Extreme Full ND Filter Kit
Cokin 67mm Nuances Vari ND32-1000
Cokin P Evo 95mm Circular Polarising Filter
Cokin NX Professional Kit
