The 4-piece set contains the ultimate OLAPLEX repair kit consisting of OLAPLEX N°.0 Intensive Bond Building Hair Treatment and OLAPLEX N°.3 Hair Perfector for weekly use to repair all hair damage. In addition, the set includes two best-sellers in travel size - OLAPLEX N°.4 Bond Maintenance Shampoo and OLAPLEX N°.5 Bond Maintenance Conditioner, which prevent frizz and damage and moisturize.Repairs damaged hair from the inside. Unlike other active ingredients, the original OLAPLEX ingredient does not work from the outside, but repairs hair from the inside out - by permanently bonding broken disulfide bridges in the hair.Application: 1.Apply OLAPLEX N°.0 in dry or towel-dried.Leave on for 10 minutes. DO NOT RINSE.2. apply OLAPLEX N°.3 to hair moistened with OLAPLEX N°.0 and leave on for another 15 minutes.3. rinse and wash hair with OLAPLEX N°4.4. apply OLAPLEX N°5, leave on for 1-3 minutes and rinse.""Only OLAPLEX® can do that.""An active ingredient that changes everything.With the paten