This is a Putra Prapti Yantra or a Santan Prapti Yantra. This Yantra is prepared to beget a child of the gender of your wishes; boy or girl. The Yantra and the mantra are both dedicated to Shiva and Durga Mata as the Shakti.
This Yantra is recommended to be prepared on Silver or a Copper. The Yantra has to be worshipped by the woman desiring a child. The mantra which I have given below has to be chanted 1008 times daily.
|Putra Prapti Yantra|
ॐ दुर्गेशमहेशाय नमः ||
Om Durgeshmaheshaya Namah ||
Then the woman must worship the Yantra everyday after chanting the mantra with an offering of milk with sugar and honey mixed in it. Then she has to keep the Yantra under her pillow, if that is not possible then she can keep it in her place of worship.