What Is This Annoying Sound? [Video]

It is, without a doubt, one of the most annoying sounds that I've heard! Can you guess what it is? Take a guess and you could win some goodies from us.

Just so you know, this audio was captured on my phone in my presence earlier this week. That's the only help you're gonna get...and that doesn't even really help ya.

So listen to the sound (if you can make it all the way through) and then submit your guess below. I'll give you a couple to days to take a crack at it. Later this week I'll reveal the answer, and I'll select a winner from all of the correct guesses (if there are any). If there aren't any correct answers, I might just pick the most creative.