The Cokin Z723 Yellow CC (CC20Y) Filter is a colour correction filter that allows you to make blue tones more neutral in your image. Ideal in an environment with predominant lighting. The abbreviation CC20Y in the name indicates that it is a colour correction filter (CC) with a density of 0.20 in the colour yellow.
To find out which correction filter you need in a situation, you can use a colour temperature meter. The Cokin Z723 filter is suitable for use in the Cokin Z-Pro series filter holder.