A curling iron uses direct heat to curl your hair, while hot rollers use indirect heat. Curling irons come in a variety of sizes, so you can choose the size that best suits your hair type and the look that you are going for. Hot rollers come in a variety of sizes, so you can choose the size that best suits your hair type and the look that you are going for. It is important to find the method that works best for you and your hair.