It's one of many cartomizer
tanks - a big tank with end caps and a steel cartomizer that has been punched or slotted in the sidewall is pressed through the tank so the tank surrounds the carto. Then the tank is filled with
juice (the carto may also need so drops added to it).
Vape-O-Matic Liquinator
These are different from CE2 tanks which just have the wick and coil guts of a CE2 carto inside.
And note - any tank that only uses dual coil cartomizers should not be used on batteries under 450mah. Dual carto cartos are very LR. Slim batteries need to use standard resistance cartos (2.5 to 3 ohms)