You guessed well, I had no clue what an ec2 was, thanks for claryfing. But sad society actually gave me the main info I needed, for using a tank you need a cartomizer.
Sorry, I am so new at this.
At the moment I am refilling proprietary cartomizers with a mini kit (E-Lite, a UK brand , I think).
I understood that you can either have separated atomizer and carton, or the two things together in a cartomizer.
So I reasoned that if there is a tank /cartridge there is no need of a carton to hold the liquid, as I read that go systems with tank don't use any foam.
But I understand that's not how it works. I never seen one, otherwise perhaps I would be less confused.