Most people have seen it, but few ever stop to think about it—the small hole at the top of many pen caps. It looks like a small design detail, but in fact, it has a very important reason behind it.
1. Safety First
The main reason for that little hole is safety. Pen manufacturers added it to reduce the risk of choking accidents.
If someone (especially a child) accidentally swallows the cap, the hole allows air to pass through.
This small design feature can literally save lives by preventing complete airway blockage.
2. Pressure Regulation
