This is cool.. An article about a ringtone that only people under 20 can hear. Almost no one over 30 can hear this frequency.
Very popular among high school students, to use it during classes without the teachers knowing =P Turned out my mum cant hear it and my friend's manager over 30 cant hear it too! I can still hear it, *phew* =P yay i'm still young =)
If you're under 20 (or over 20 with very good hearing), you can listen here
wow that's cool!! yeah my mum couldn't here it either.. i could barely hear it myself.. it gives me a headache!! So high pitched!