There is a relatively new device called "The English Mosquito" which is being used in England to control where young people typically gather. The device works by emitting high-frequency sounds that only young people (typically younger than 20 years of age) have the ability to hear. Because it's fairly annoying, it causes young people to eventually leave a particular area. Human right's groups are obviously unimpressed with the blanket use of the devices: Aynsley-Green said about 3,500 of the devices are in use across England to split up gatherings of youth in areas such as parks and ...