What's the difference between the Zenith and the Zenith D22 tank?
There's a slight difference in the width (diameter) of the tanks, with the original Zenith being 24mm and the Zenith D22 standing in at 22mm. They both have the same e-liquid capacity of 2ml, so it's just a case of which would look best on your mod/battery.
How do you fill the Zenith D22?
Simply twist the top of the tank to expose the filling hole, and squeeze in your favourite e-liquid until it's full!