See this article https://support.google.com/merchants/answer/6324478?sjid=16926776345918052889-EU
To do this you will likely need to set this field up as a product metafield
See this article https://support.google.com/merchants/answer/6324478?sjid=16926776345918052889-EU
To do this you will likely need to set this field up as a product metafield