A small Valleys firm hopes its high-pitched alarm originally meant to repel youngsters from shops could become the latest teen ringtone craze.
The "Mosquitotone" will be on sale all over the world
Merthyr Tydfil-based Compound Security's "Mosquitotone" has now been filling column inches as far afield as the New York Times.
It was developed because adults lose an ability to hear high-pitched sounds.
But teenagers turn it to their benefit with a tone which lets them hear their mobiles ringing without adults knowing.
Now the firm is developing an official version which it hopes will be sold all over the world.
The New York Times reported on Monday how the ringtone had baffled teachers at a school in Manhattan.
"When I heard about it I didn't believe it at first," said Donna Lewis, a technology teacher at the Trinity School in Manhattan.
"But one of the kids gave me a copy, and I sent it to a colleague. She played it for her first graders. All of them could hear it, and neither she nor I could."
It first arrived in classrooms earlier this year when a Scandinavian teenager, inspired by the Mosquito alarm, developed a high-frequency sound into a ringtone.
The "teen buzz" is said to have spread to the UK and America via the internet.
The alarms were originally designed by the Welsh business to repel gangs of young people from loitering around shopping centres without upsetting adult customers.
Marketing manager Simon Morris said the firm, which has a staff of two, were "gobsmacked" by demand.
"It seems to be popular with teenagers because it's one in the eye for the authorities and rules," he said.
Mr Morris denied there could be a moral problem with the product and said the firm was satisfied it could not be used for bullying.
"If kids want to use their mobile when they shouldn't be, they can already set them to vibrate or put them on silent, so it's not going to make any difference," he said.
"It's a bit of harmless fun really, isn't it?"
Teacher Suzanne Nantcurvis from Ysgol Dinas Bran in Llangollen, said she did not think the new ringtones would disturb many lessons because for most pupils mobile phones were not allowed in schools.
"If pupils do not hand their mobile phones in and they go off in class they are seriously reprimanded," she said.
Compound Security's 17 kilohertz version of the ringtone went on sale on Friday in the UK for £3 and so far about 1,000 people have bought it.
They are also available in the US and should go on sale in most countries around the world by the beginning of next week, said Mr Morris.
The firm is also considering producing melodic ringtones at a high pitch and a £500,000 TV and radio advertising campaign begins before the end of June.
"Experts we've spoken to in the industry say it's going to be bigger than the Crazy Frog," Mr Morris added.
He said he and managing director Howard Stapleton had thought about turning the alarm into a ringtone, but did not think there would be a market for it.
But the attention the Scandinavian-produced ringtone received prompted the firm to launch an official version of the high-frequency sound.
A condition called presbycusis, or ageing ear, means that by the time most people reach the age of 25, they cannot hear much above a frequency of 13 or 14 kilohertz.