The developer of DC's Gallery Place, a busy mix of retail shops and restaurants, is trying a controversial measure to keep teens from loitering: The $1,000 device is called the "Mosquito," and it emits a piercing, high-pitched tone that is supposed to be audible only to young people, explains the Washington Post. For the technical minded, its tone of 17.5 kilohertz is the high end of the range of hearing for those ages 13 to 25.
"The bottom line is that the Mosquito is installed where 13- to 25-year-olds aren't supposed to be," says the maker. "Adults just walk through the sound." The device has generated plenty of complaints, and some lawmakers are already backing away. Still, some adults—who remain blissfully deaf to the Mosquito's tone—like the idea. "I think it's a good thing," says one 40-year-old resident. "All the youngsters do is fight."