This guy invented a device that he says emits sounds only young people can hear – it’s used to chase them away and stop them from doing bad things. Nooo!! Not the Ludwig Van, and the dreaded Ninth Symphony! “Howard Stapleton, inventor of the Mosquito, with a speaker mounted on the wall behind him, at a store in Barry, Wales, where boisterous teenagers once gathered. The device projects a very shrill and very annoying tone that only youths can hear. Then they flee.” Thanks Nick! Link.
Sonic teenager repellant