Ai Dolls are small ball jointed dolls, they are slightly less than five inches tall. Ai dolls are made of plastic so they are not on topic on Den of Angels. There were four different facemolds used for releases (two different open eye molds, a partially open eye mold and a closed eye mold). The first release was in early 2007 they were released regularly until 2012 when there schedule became more sporadic, the last one was released in May of 2013. As of this time it is unclear if the line will be continuing or not as no additional releases have been announced.
Further Reading:
Complete release list of Ai Doll
Ai Doll FAQ
Ai Doll Face Up Index (Only Partial)
Review Tsubaki
Owner Photos
Pullips and Junk 
I love your page a lot! Do you know about the Ars Espe dolls? They look similar to Ai dolls but they’re taller. They’re also made by Groove and Ars Gratia Artis. More power to you! ❤
Thanks ^_^ I am aware of the Ars Espe dolls, I do not own any as only two were ever released by AGA. They weren’t ever available in the US and they are kind of rarely seen/heard of I don’t think I’ve ever even seen an owner photo though they do pop up on Yahoo Japan from time to time.