(WJW) — It’s billed as an anti-loitering alarm — and it’s specifically designed to keep away teens. The device sends out a noise that only young people can hear. And some people are spending thousands to keep teens away from their property.

It’s called the Mosquito and is now being deployed at businesses, public parks and schools across the country to deter aggressive panhandling, vandalism and other illegal activity.

At least 20 parks departments and the city of Philadelphia admit to using the Mosquito to reduce gang activity and other issues.

FOX 8’s Suzanne Stratford goes behind the scenes to find out how it works. Watch in the video above.