Pen Cap Holes
At a glance, you might think there is something wrong with the pen cap because there is a hole in there. Do not worry, this was all done by design. It was installed there so air can freely flow in if it is accidentally swallowed by a kid or adult. This makes sense because there are a lot of people who like to put the pen caps in their mouths when they are thinking!
Pen Cap Holes
iPhone Camera Hole
If you own an iPhone, you might have noticed the little hole beside the camera lens. Anyway, the small hole is not a secret camera. It is a microphone! Since Apple introduced the iPhone 5, every smartphone comes with three mics. One is located under the speaker grill, another on the bottom edge, and the last one is beside the camera lens. This makes it easy to record sound no matter how you hold the phone.
iPhone Camera Hole
