Sorry to say, I recognize that tank from gotvapes:
(cross-post)
gotvapes copy translated:
I was looking at their new carto tanks:
"Very attractive 3.0ml carto tank, extremely well sealed. You can disassemle
(sic) the tank from this unit but it is so well sealed into the top and bottom o-rings that you are instead provided a top knurled screw-in fill port through which you can fill your tank without removal of your cart!"
Translation: You need a wrench to get the carto out. Not true.. removal was not hard at all
"Earlier releases of the X series tanks provide a machined hole at the base but no extra screw. Many speculated this was to hold the top screw when refilling so as not to lose it. We surmised it may be there to provide additional air flow control."
Translation: The first version leaked. The second version came with a screw we thought was supposed to stop the leaking, but it doesn't; it also leaks. We don't know what the screw is for. Bob, in sales, speculated, while Jim, in receiving, surmised it has a purpose. (Bob's wife also speculated, which counts as "many.")
No leaks, I think it helps stop and stablize the tank to the carto.
"With its clean quasi-steam-punk appearance, stainless tip and highly polished top and bottom caps you simply have a nice sophisticated entry and somewhat low-profile entry into the carto tank market. This is a KEEPER!"
Translation: No warranty; no returns. It doesn't come with directions. You have to keep it no matter what.
Note: Quasi-steam-punk? Sophisticated? Low-profile? I suggest you pick a theme and stick with it. Those descriptions aren't quite synonymous.
"The tube can be removed but it is very tight. You will need to use your thumbnail to wedge at the top of the tube and bottom to wiggle it off. We suggest removing the bottom screw to provide air displacement to make this easier."
Translation: You need a wrench.
"You do not have to use the bottom screw and not using it or adjusting it MAY provide more airflow if desired. We haven't verified this."
Translation: We REALLY don't know what the screw is for.
"We would suggest keeping fill screw in the fill port to provide proper vacuum pull and also to avoid misplacement."
Translation: If you don't use the easily lost fill-screw the tank will leak from the top too.
It was also described as "nifty" somewhere in the listing.