WASHINGTON (AP) — The number of different e-cigarette devices sold in the U.S. has nearly tripled to over 9,000, despite a three-year effort by the Food and Drug Administration to crack down on kid-friendly flavors.

The rise in electronic cigarettes has been almost entirely driven by a wave of cheap, disposable devices imported from China.

That’s according to sales data obtained by The Associated Press.

Most are sold in fruit and candy flavors that can appeal to teenagers.

All are technically illegal, but they continue to flow into U.S. ports with little threat of retaliation.

The trend underscores the FDA’s inability to control the tumultuous vaping market previously dominated by Juul and other reusable e-cigarettes.