Tape-in extensions are lean grains of hair attached to a double-sided, adhesive tape. These extensions are applied by sandwiching a small segment of all-natural hair between pair of tape wefts, producing a smooth mix. The method is faster and also much less invasive than typical techniques like building or even embroidery. Read for more info here: http://hairdryerfair.com/do-tape-in-extensions-damage-hair-what-you-need-to-know-about-it/