The Messenger of Allah ﷺ said, "The divorce of a slave-woman is two pronouncements, and her waiting period is two menstrual cycles."Muhammad bin Yahya said, Abu Asim narrated to us, saying, Muzahir informed us of this.
حدثنا محمد بن يحيى النيسابوري حدثنا أبو عاصم عن ابن جريج قال حدثني مظاهر بن أسلم قال حدثني القاسم
أن رسول الله ﷺ قال طلاق الأمة تطليقتان وعدتها حيضتان قال محمد بن يحيى و حدثنا أبو عاصم أنبأنا مظاهر بهذا
Its chain of transmission is daif. Abu Dawud reported it in the Book of Divorce, chapter on the sunnah of the divorce of a slave, no. 189, and Ibn Majah reported it, no. 2080, both from the hadith of Abu Asim, with the same chain. Abu Dawud said, this is an unknown hadith. Mazahir bin Aslam is daif, as stated in Taqrib Tahdhib and elsewhere. On this subject there is also a narration from Abdullah bin Umar [Ibn Majah, no. 2079].