Students in the UK have been caught using a cell phone ringtone in class that can’t be heard by older people, including teachers. Due to the progressive loss of hearing as we age, most people lose the ability to hear this high-pitched sound sometime in their 20’s. Link

The ringtone was adapted from the Mosquito Alarm which is marketed to store owners in order to keep teenagers from congregating nearby.

Can you hear it? If you don’t hear a high-pitched chirping sound and only hear some background noise, consider yourself immune to this “teenager repellant.”