How does a device called 'teenager repellent' work?

it sends ultrasonic waves in the air that only young ears can detect, it is also called the mosquito or something like that. ( i think)How does a device called 'teenager repellent' work?
I have found that the best 'teenager repellent' is music by Lawrence Welk, played at extreme volume.





There is some electronic device which is supposed to emit a sound that is apparent only to teenager's ears and unliked by them.





I don't like Welk myself, but I can always put on the headset and crank up AC/DC or Zep or someone.How does a device called 'teenager repellent' work?
No idea - I imagine it might have the scent of lavender water about it. (It probably causes the wearer to wear a pork pie hat and a quilted nylon anorak too.)
It's a box that emits a high frequency sound that only teenagers can hear for some reason. I don't know why. It's suppose to be really loud and hurt your ears to listen to it. There's an article I found linked below.
I think you are talking about the Compound Security Systems ';Mosquito Device';.


This emits a loud noise at 17.4 kHz frequency, which is too high-pitched for most adults (over 20 yo) to hear, but which is very loud and annoying for teenagers.





It works because of Presbycusis, a loss of hearing of high-pitched noises that is normal with increasing age.The noise is loud enough to annoy but, at 75 dB, not loud enough to damage hearing.





Others have taken advantage of this to develop a ringtone (';TeenBuzz';) that can be used as a mobile phone text alert by pupils in class, so their teachers cannot tell that they are receiving texts.
the ';mosquito'; emits a radio frequency between 20,000 and 22,000 hertz wich is to high pitched for adult ears
it puts off a sound that is annoying to a teenager, so they leave the area. much the same as a parent asking where they are going, or for them to clean the house, do the dishes, walk the dog, get a haircut.