This is a FCS-only head mold. It was released at Tenshi no Sato in June 2015. The Full Choice Handbook: 2016 by Volks shows the head mold with 16mm eyes, and notes there are teeth that are visible that can be painted. This head was a Sato exclusive. On September 15, 2018 this head was made avaiable at all Sumika locations.
Please click on the individual thumbnails to see the pictures full-sized.