Padlocks are everyday tools we use to protect bikes, sheds, gates, and toolboxes. They seem simple, but their design includes small details that help them last—especially outdoors. One feature many people overlook is the tiny hole at the bottom of the lock. Though it appears insignificant, it plays an important role in keeping the lock working properly.

The main purpose of this hole is drainage. Since padlocks are often exposed to rain, humidity, and condensation, water can easily get inside. If moisture stays trapped, the internal parts can rust or corrode, causing the lock to weaken or jam. The small hole allows water to escape, protecting the mechanism and extending the life of the lock. It also provides a convenient spot for adding lubricant if the lock becomes stiff.

This idea of hidden features appears in many other everyday items. Some screwdrivers, for example, are designed to fit into the round opening of a wrench to give extra leverage in tight spaces. Clothing often comes with a tiny fabric swatch, which can be used not just for laundry testing but for repairing small tears or matching thread.

Even vehicles include subtle details that help us without thinking. The small arrow next to the fuel gauge points to the side where the gas tank is located—handy when driving unfamiliar cars. And the number “57” on Heinz ketchup bottles marks the exact spot to tap to make the ketchup flow smoothly.

These small, clever features show how simple design choices can make everyday life easier—sometimes starting with something as tiny as a hole at the bottom of a padlock.