The Cokin Filter Z717 Magenta CC (CC40M) is a colour correction filter that allows you to make green tones more neutral in images. Ideal in an environment with predominant lighting. The abbreviation CC30M in the name indicates that it is a colour correction filter (CC) with a density of 0.40 in the colour magenta.
To find out which correction filter you need in a situation, you can use a colour temperature meter. The Cokin Z717 filter is suitable for use in the Cokin Z-Pro series filter holder.