A new report from the Centers for Disease Control says one brand of e-cigarettes has become especially popular among young people.

Juul, an e-cigarette shaped like a flash drive, has seen sales skyrocket over the past year, especially with a younger market.

The CDC report indicates Juul is being used in schools, including in classrooms and bathrooms, more often than before. The concern, according to the CDC, is that these products include the addictive substance nicotine, which has been known to harm brain development in young people.

An owner of a Brooklyn vape shop, though, says Juul makes it almost impossible for minors to buy products on their website, asking for verification and identification. The owner says it is unfortunate the products end up in the hands of minors, but also notes that businesses like his that ID every customer are not to blame.

The CDC report says sales have skyrocketed for Juul among young people because of their wide variety of flavors.