The Cokin Filter X020 Blue (80A) is a colour correction filter that adds a cool colour tone to your images. Warm tones become more blue. With a size of 130 by 170 millimetres, the filter is suitable for use in the Cokin BX-100A filter holder. The 80A addition means that this filter can correct colour temperatures between 3200 and 5500 degrees Kelvin. Think for example of the standard lamps at home.