Soldato
Not sure if they changed the coils on the 4th version, but there's a rebuildable 3rd party coil for the first two versions. I've been using it since the v1 and v2 came outMost of the new pod-systems are both refillable and have replaceable coils. I use a Smok Nord 4 when I'm out and about. SMall enough to fit in my trouser pocket and doesn't cost the earth to run due to the aforementioned replaceable coils and refillable tanks.