 The study examined public discourse on Twitter referencing both puff bar and JUUL e-cigarettes, finding common themes such as flavors, health risks, and potential substitution for one another. The results aim to inform the tobacco control community about popular e-cigarette products with different features that can be potentially substituted for one another, and suggest future health communication campaigns should target the health consequences of using multiple e-cigarettes or dual use to reduce exposure to high levels of nicotine among younger populations. This article was authored by John Patrick Allam, Allison Dorminesh, Anu Jamaj Mandar, and others.