it's 18.8mm or 19mm. same thing, some call it 18.8mm some 19mm.
@Shit Snacks that was my point! I felt something was not ok. buying batteries from amazon is bad unless you buy it from "Amazon seller" or so, and you have to triple check it. I guessed he knew (and he did) how to take a draw! and he said he was reading the manual, so he knew what to do
but I'll ask the next user if he knows how to take a draw, before the debugging.
Debugging is like: -Do you know how to use this device? did you read the manual+watched atleast 1 review? are you focused?
--What's the resistance? did you change it? Which temp/wattage is set?
---Which batteries you use?