Have you heard of JUULing? If you’re the parent of a teenager, you may want to know about this trend. JUULing describes the use of a specific kind of e-cigarette that has skyrocketed in popularity among teens.

A JUUL e-cigarette doesn’t look like a cigarette at all. The small and sleek device is shaped like a flash drive and charges through a USB port. A starter kit costs about $40, and its cartridges come in flavors like mango, crème brulee and mint.

But here’s the problem: Each JUUL cartridge contains as much nicotine as a pack of cigarettes. And when used, the device emits only a light vapor, making it easy for teens to hide and use discreetly.

By law, you must be 18 to buy a JUUL, but school officials and health groups are seeing teens use the product in middle and high schools. School districts in several states, including Kentucky and California, have implemented policies to address the use.

Why should parents be worried? JUUL is marketed toward adults as an alternative to cigarettes, but its popularity among teens is troubling. According to the Centers for Disease Control and Prevention, teens are significantly more likely to use e-cigarettes than smoke cigarettes. Vaping is considered safer than smoking cigarettes, but the CDC warns there is not yet enough research to determine the health effects of vaping, and it does expose people to chemicals that cause cancer. Nicotine exposure can harm teenage brain development and cause addiction.

If you’re a parent, have a conversation with your kids about JUULing and the health effects of using e-cigarettes. If your son or daughter does vape, work with him or her to kick the habit.