3 different vape pen electronic cigarette devices juul, aspire breeze, smok infinix, product shot isolated Stock Photo Alamy The Juul vaporizer can be disguised as a Sharpie or a USB stick, and contains nicotine, glycerol and other chemicals. Teens say they don't vape, they 'Juul.' That makes the activity hard to track Los Angeles Times Vape devices like Juul 'reversing' efforts to keep youth from tobacco: study