Privacy screen for your laptop webcam. Just clip it on when you don't want to be spied upon! Fits most sizes from thin to medium thick laptop screens.
The idea behind it is that if you like to work with your underwear wrapped around your head at home like I do most of the time... and don't want some ratters to record a video of that and post it on YouTube, then you'd be on the safe side with this covering the lens of your webcam. Because let's be honest. When you are concentrating on your screen, would you really notice the light of your webcam come on?