Switch on the small, gray metal box and listen: A sharp, pulsating, high-pitched tone burrows into the ear like a power drill, prompting an agitated, please-shut-that- blasted-thing-off grimace. That's what you hear if you're between the ages of 13 and 25.
If you're not, you might not sense a thing.
Howard Stapleton can't hear the sound he conjured up three years ago. His daughter, Isobel, 15 at the time, had come home in tears from a store in their town in South Wales, after having been harassed by other teens.
The store owner told Stapleton that he and other merchants and customers wanted the young toughs gone, too, but feared a confrontation.
As the security device inventor contemplated the problem, he recalled from his teens the awful buzz of an ultrasound welding machine at his father's glue-plastics factory. He remembered that his complaints about the noise would be met with a quizzical look from workers: "What noise?"
From that impulse to help rid his local market of loiterers came his invention, "the Mosquito," an electronic contraption that emits a high-pitched pulsating sound that can mostly be heard only by teens and people in their early to mid-20s. It works because an age-related hearing loss called presbycusis reduces the ability to hear high-pitched sounds after the late 20s. The device is mostly inaudible to older adults, young children and pets.
In Britain, the Mosquito has become the next big thing in crowd and crime control - and it may one day be coming to a teen hangout near you. The device seems to have ratcheted up the aural warfare that began a few years ago when train stations and merchants in England and elsewhere tried piping in classical music to repel young loiterers. It entered the U.S. market last fall.
The Mosquito emits a sound that can be heard up to 60 feet away for 20 minutes at a time. It can be heard through earphones and over loud music. It is for commercial and official use only, and is never supposed to be used in a residential area or near a bus stop, the manufacturer says.
Young people, meanwhile, have turned the table on the technology. Many have downloaded the sound onto their cell phones, creating a ring tone that they can hear but older adults can't. Teen Buzz, a short Mosquito ring tone, has become among the most downloaded ring tones worldwide. Some use it to alert high school classmates of recently sent text messages. For others, it's come in handy when parents curtail use of their cell phones.
