I have two of the mini Vivi's and love both of them. One thing that is different between the two is the threading for both ends. One is on the inside of the tube and the other is on the outside. Which one is the "genuine" style? I don't remember where I got the one from that has it on the inside. I got the one on the outside from madvapes. I do know it is a knock off which doesn't bother me. But the tank has cracked for some reason. I have ordered two tubes so far. First time I ordered off MV but they only have the 3.5 ml size which I didn't notice until I received it. I then ordered a 2.0 ml tube from elsewhere and the threading was on the inside just like on the big tube. I also didn't notice this until I received it. It fits my other Nova so it's no big deal. My main question is what is going on and where do I get a 2 ml tube with threading on the outside?