A shop manager's annoyance over problem teenagers hanging around his store is being tackled head on with a noise nuisance device.
The small black Mosquito device is on the front of the Spar shop
The Mosquito, which sends out high-pitched soundwaves, is persuading gangs to move on.
Robert Gough, who runs the Spar shop in Barry, says the new nine-inch box is a success.
As treasurer of PACT (Preventing Anti-Social Crime Together), Mr Gough hopes more businesses will be helped.
The box, placed on the outside wall of the store, emits an 80-decibel pulsing frequency between certain hours.
Many older customers cannot hear it - but teenagers, who previously congregated in the evenings - have complained to Mr Gough about the noise.
"Not everybody can hear it but definitely most teenagers can," he said.
"We just put it up and said nothing to the teenagers, then they came in to complain. They were literally begging me to turn it off.
"I told the kids it was to keep the birds away because of the bird flu epidemic. They waited for their friends and left covering their ears," added Mr Gough.
Robert Gough says the problem of youngsters is worse at night
Mr Gough says gangs of around half a dozen up to 30 people have been hanging around the shop.
"They usually move on if I ask them but the problem has always existed," said Mr Gough, who has run the shop for 15 years.
The shopkeeper, aged 34, said: "I can hear it as well. My son's 14 and my daughter's 12 and it really irritates them. If we are standing here they say 'Come on dad, let's get in the car'."
Mr Gough said he was "very pleased" with the results and claims shoplifting has also dropped.
Shopper Gerda Hunt, aged 62, said: "I could hear it last night but I can't hear it now.
"It's like a buzzing noise, I didn't know where it was coming from, it's not terrible."
One seventeen-year-old, who did not want to be named, said she thought it was the device was a good idea.
"It's like a high-pitch buzz. My dad comes here a lot and he hates it," she added.
Inventor Howard Stapleton, of Compound Security Systems in Merthyr, said the idea was born after he was irritated by a factory noise when he was a child.
Years later, he thought about deterring youths from a Merthyr shop and tested a device at a Penydarren shop.
He said the Mosquito emits several tones all in and around 16Khz.
Mr Stapleton said he has spoken to Defra (Department for Environment, Food and Rural Affairs) and his local environmental health department about the invention.
Audiologist Roger Lewin, from the British Society of Hearing Aid Audiologists, said the noise could be heard by any age and would depend on the level of hearing.
He said concern could arise if anybody had to listen to it through no choice of their own - such as a shopworker or a baby parked in a pram outside the shop.