Hair extensions can be either from real human hair or synthetic. The extensions are braided or woven into the natural hair of the wearer, so that they are secure. There are some types that are stuck to your hair (eg Tiffany Twist do-it-yourself HOLLYWOOD HAIR™ is a strand-by-strand, home application system that is sold directly to the user in an at-home kit. Tiffany Twist do-it-yourself HOLLYWOOD HAIR™ is 100% human hair and is safely bonded into your hair, by you, and does not need to be removed daily. The hair extensions can be washed, slept in and styled just like your own hair. You can wear your extension hair for weeks with the confidence of a secure hold, free of pulling and headaches. There are no glues or chemical removers involved! You can easily remove your extension hair yourself, in seconds. When you're ready, simply bend to break the bond, the TemBond™ crumbles, and your extension easily falls away. The Tiffany Twist do-it-yourself, HOLLYWOOD HAIR™ home hair extension kit contains quality, soft and silky, 100% human hair that can be used over and over again, 6 ounces of TemBond™ (for up to 4-6 applications), a warmer for the bond, clips and comb, step-by-step instructions, care and tip sheets; everything you need to accomplish your own hair extension application. Visit www.tiffanytwist.com/hair for information, photos, and video. ) Here is a site that explains how they do hair extensions: http://www.hairboutique.com/tips/tip034.htm