A bobby pin is a small, thin piece of bent metal wire used to hold hair in place. The pin forms a tight zigzag or wavy shape that grips strands of hair when you slide it in. One side is usually smooth and rounded, while the other has ridges that help it grip better.

These pins helped keep short, bobbed hair neat and styled. Before elastic hair ties became common, bobby pins were one of the main tools people used to manage their hair.

You'll find bobby pins everywhere: dancers use dozens to secure their hair in buns, actors use them backstage to prepare for performances, and people use them daily to pin back bangs or hold a braid in place. They're so useful that people have discovered other purposes too, like holding papers together in a pinch.

The pins are typically black or brown to blend with hair color, though you can find them in other colors too. Despite being small and easy to lose, a single bobby pin can make the difference between a hairstyle that stays put all day and one that falls apart by lunchtime.