It could also be the M218B.
https://www.mobileread.com/forums/sho...ighlight=m218b
According to
Engadget, Group Sense developed a GSM (cell phone modem) module that is compatible with many different devices including the M218B ebook reader, which is made by JCNIP.
So the device isn't new, but I for one didn't know that it had an expansion slot. Interesting.