Indication Our Hair extensions are the easiest, safest, and fastest ways to add length, volume, and color without the need to visit your stylist. No harm to your hair from bleaching or dyeing. Material Composition 100% High Quality Korean Heat-Resisting Synthetic Fiber Instructions for Curls It is best to not use hot hair curlers on the extensions unless the temperature is set to the lowest setting. Even then we recommend you not to use them to extend the product life. To curl your extensions, you can use hair-curlers to set the shape of the extensions after dipping the extensions in hot water (not boiling hot). Leave them to dry naturally, and remove the curlers once the extensions dry. Your extensions should now be curly.