We have heard of ultrasonic insect repellers which emit ultrasonic frequencies to repel the pests. From a Welsh inventor comes the Mosquito which uses the same technique to repel teens. The Mosquito emits an ultrasonic sound which can be heard by most kids and teenagers only while remaining unaudible to adults over 30 due to deterioration of hearing ability with the age. It has a effective range of 15 - 20 meters and for all you PETA activists out there it does not bother dogs. The Mosquito has been installed at various location across the UK and has been successful in driving away rowdy yobs.