18" Wavy Clip In Hair Extensions by Hairdo is an 8 piece clip in extension system which adds length and volume in an instant. Working with several individual wefts in different sizes, you can use as many or as few as you want... depending on your style! Pressure sensitive clips are around the base for securing to your hair. Made with heat friendly synthetic hair which can be curled or straightened with heat styling tools. Affordable, lightweight and easy to attach, these virtually undetectable clip in hair extensions can be put in and taken out in a matter of minutes.