I think mine is like the mini Vivi, but not sure because there is some different models that have a name with Viva in it. The one I am using and like, is the Vision Vivi Nova 2.5ml size and that is the small one. The other is a bigger 3.5ml and is larger than what I like so, I have the 2.5ml one and they are harder to find. There is a lot of the larger ones, 3.5ml at various vendors and you can get metal colored ones for the tanks but have not seen metal for the smaller 2.5ml version, and I buy the long wick replacement atomizer heads.
Yeah, I have both those, and like them both. But I like the mini better these days. I'm gonna put
a new head on the larger one, and maybe I'll start liking it better again.