I saw a short video of Sondors thin model ebike. It stated it is belt drive. I cannot find this on their website. The "Thin" model shown looks to be chain driven. Is the belt drive model an older design?
I am not sure about the "thin" however, I was looking at the mid-drive cruiser and noticed that the seat stay has a break in it. That leads me to think that a belt drive may be in the roadmap for that model.