This is the same head mold as SDM standard models Dai and Mako. It was released at Tenshi no Sato in March 2016, then was made available to all Sumika in September 2016. The Full Choice Handbook: 2016 by Volks shows the head mold with 16mm eyes, and notes there are visible teeth that can be painted.

This is a quote from Volks Facebook page promoting the mold for NA Online FCS.
"Their small cute demeanor with bright big eyes and adorable duck lips are delightful! As a girl, we get a feeling of a sweet younger sister who we just want to braid her hair and spoil with ice cream! As a boy, we get a feel of a mischievous younger brother who only causes trouble to get your attention."

Please click on the individual thumbnails to see the pictures full-sized.