emailinvitation from Pax Labsfor the launch party of the company’s “revolutionary new vapor product, Juul.” When she walked into Jack Studios in Manhattan’s Chelsea neighborhood, in June 2015, the teen — who was an occasional cigarette smoker — saw a dance floor full of influencers and tastemakers, all puffing on sleek 4-inch devices that looked like USB drives and tasted of flavors such as mint, crème brulée and mango. Above her, screens flashed hashtags like #Juul and #JuulVapor along with real-time Polaroids of attendees vaping.