Padlocks are small but powerful tools for protecting bikes, sheds, toolboxes, and more. Many people don’t realize the tiny hole on the bottom has an important purpose: it lets water drain out so the lock doesn’t rust from rain or moisture. This simple feature helps the padlock last longer, especially in harsh weather.

The hole also serves another function—if the lock becomes stuck, you can add lubricant through the opening to help it unlock again. While modern weatherproof padlocks exist, the classic design remains useful and clever.

Other everyday items also have hidden features. Screwdrivers can fit into wrenches to reach tight spaces. Clothing swatches help with color matching and testing detergents. Brass doorknobs are naturally antibacterial. Cars have a gas-tank indicator arrow on the dashboard. Even the Heinz 57 label on bottles marks the best spot to tap for smoother pouring.

These small design secrets show how everyday objects are built to make life easier—often in ways we never notice.