The Cokin Filter P022 Blue (80C) is a colour correction filter that adds a cool colour tone to your images. Warm tones become more blue. With a size of 85 by 85 millimeters, the filter is suitable for use in the P-series filter holder. The 80C addition means that this filter can correct a colour temperature between 3800 and 5500 degrees Kelvin. Think for instance of reportage flash units.