What tool is commonly used for creating volume at the roots of hair?

The teasing comb is specifically designed for creating volume at the roots of hair. Its fine teeth are ideal for backcombing or teasing, which involves gently pulling sections of hair upward and creating tangles to add height and fullness at the scalp. This technique is particularly effective for achieving styles that require more lift or texture, such as updos or voluminous hairstyles.

The other choices, while useful in various hair styling techniques, do not serve the primary function of adding volume at the roots. A round brush is typically used during blow-drying to create smoothness and some volume but does not specifically target root elevation like the teasing comb does. A flat iron is used for straightening hair and creating sleek styles, and it does not add volume at the roots. Hair clips are primarily for sectioning hair during styling and do not contribute to volume.