Hair curlers are tools used to create curls or waves in hair. They come in various types, including heated curlers, foam rollers, and Velcro curlers. Heated curlers use heat to shape the hair, while foam rollers and Velcro curlers rely on the hair's natural ability to hold a curl as they set. Using hair curlers can enhance hairstyles for special occasions or everyday looks. They are available in different sizes, allowing users to achieve tight or loose curls depending on their preference. Proper use and technique can help maintain the curls for longer-lasting results.