How To Apply: Shrinky hair extensions are applied using is a strand-by-strand hair technique. You basically section off the hair and thread each shrink-link (or shrink-tube) into your natural hair. A pre-bonded / keratin-fused strand of extension hair is placed inside the tube. Using a special heat clamp, the keratin fuses the extension and natural hair creating a bond, and the tube shrinks to protect the bond. It’s important to use a professional salon with the proper tools (i.e., special heating clamp, quality Shrinkies) so they are installed correctly, look their best, and last longer.