If you are asking about the tatroe tank cig tecks has them. They are in the usa, they have the bases also, if that is what you are asking for.
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Provape also sells the Tatroe bases and rings. But, I couldnt find a way to buy the rings separately; I could only buy a ring as an option for the base. Also, I couldnt find a way to order more than one ring from Provape.
The last time that I checked, however, it was cheaper to buy them from Cigtechs (not including shipping).