Not all electronic cords look the same. Some have two prongs; others have three or even four. Some have prongs at weird angles, or are even designed for orange electrical outlets . Odds are most people have also seen electrical prongs with holes in them, but the reason for them isn’t common knowledge.

Those two tiny circles often appear near the ends of the metal blades, and newer outlets no longer depend on them. Learn how the feature started, why some manufacturers still use them, what homeowners should know about plug safety, and more.

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Why Do Electrical Plug Prongs Have Small Holes in Them?

What Are the Holes in Electrical Plug Prongs Used for Today?

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Why Do Electrical Plug Prongs Have Small Holes in Them?

The holes originally helped keep plugs from slipping out of outlets. Some older outlets had small bumps inside that fit into the holes when someone plugged something in.…