Which heating tool is most commonly used for curling hair?

The most commonly used heating tool for curling hair is a curling iron. Curling irons are specifically designed with a cylindrical barrel that allows users to wrap sections of hair around it to create curls and waves. The design of the curling iron enables the stylist or user to control the size and tightness of the curl by adjusting the size of the barrel and the amount of hair wrapped around it.

Flat irons are primarily designed for straightening hair, though they can also be used to create waves with a different technique. Hair dryers are intended for drying hair and can sometimes add volume or speed up the curling process when paired with other tools, but they do not curl hair directly. Crimpers are used to create a textured, zigzag pattern in the hair rather than traditional curls. Therefore, when looking for a tool specifically tailored for curling, the curling iron is the optimal choice.