A hair iron, commonly known as a hair straightener, is a styling tool used to straighten or curl hair. It consists of two heated plates that clamp together, allowing users to glide the device through sections of hair. Hair irons come in various sizes and materials, such as ceramic or titanium, which can affect heat distribution and hair health. Using a hair iron can help achieve sleek, smooth hairstyles or create curls and waves. To protect hair from damage, it is advisable to use a heat protectant spray and adjust the temperature based on hair type. Regular maintenance, such as cleaning the plates, can prolong the tool's lifespan.