- Invented by a former electronics apprentice at British Aerospace, the device emits an extremely high-pitched noise (16kHz) which sounds like a very angry insect (hence its nickname, the Mosquito) or, alternatively, a very badly played violin. Those who can hear it find it so uncomfortable that they have to leave the vicinity. However, it is so high pitched that only people under the age of 20 can hear it, thus making it ideal for driving disruptive teenagers out of shops.
— Larry, Attack Monkey, Light Reading