I don't know what your vaping style is or if you rebuild, but that NRG PE tank that comes with the Swag 2 takes the Ijoy EXO-S RBA, which is still available from
Amazon in a 5-pack. Turns it into a single coil DL/RDL rebuildable tank. In my personal opinion, it also makes for a decent MTL if you close the airflow down to a hair and use an MTL drip tip.
Just make sure that you got the
NRG PE tank (knurled airflow control) and
not the SE. I know the Swag 2 kit box says that it also comes with the SE (must be for the TDP market but best to make sure you got a PE not an SE). The RBA won't fit in the SE.