Elf Bar is manufactured by Shenzhen iMiracle Technology part of Heaven Gifts family of companies.
Esco Bar, the worst of them is made by Shenzhen Innokin Technology Co. Ltd.
Flum is manufactured by Flumigo Technology Limited, self held company.
Juul Labs spun of from Pax, 35% of it is owned by Altria aka Philip Morris who make NJOY.
All different parent companies and hardware manufacturing plants as far as I can tell.
"The scientists analyzed the metal and metalloids inside seven types of disposable devices from three of the most popular brands. Using an instrument to activate the disposable e-cigarettes and heat the internal liquid, they created between 500 and 1,500 puffs for each device. They found:
Some devices emitted surprisingly high concentrations of elements in the vapor, including antimony and lead. Levels of chromium, nickel and antimony increased as the number of puffs increased. Most of the disposable e-cigarettes tested released markedly higher amounts of metals and metalloids into vapors than earlier, refillable vapes."
https://www.ucdavis.edu/news/disposable-e-cigarettes-more-toxic-traditional-cigarettes
https://pubs.acs.org/doi/10.1021/acscentsci.5c00641
The juice itself is... of moderate known negative impact. The nicotine itself isn't actually very bad for you. Some of the flavoring though is pretty questionable. Compared to combustion it is likely still quite a bit less negative for your health in most cases.
The exception is the hardware, it seems quite likely there is mass lead and other heavy metal poisoning happening due to poor quality metal and ceramic components in vape hardware. I work in a related industry, and this conversation is being had internally by the big players who are afraid of potential class action lawsuits coming down the pipeline while pure export companies from China and elsewhere sell bulk wholesale of low quality hardware. Vapor composition certifications are coming soon, but the damage may well be done for a generation.
Yeah or "Feed", if anything needs regulation it's this tech.
Think Clockwork Orange scenario. Hard not to think words when you are shown those things in images, and especially if you're drugged.
Now here's a real gateway drug.