The Nº.0 Intensive Bond Building Hair Treatment, infused with patented OLAPLEX Bond Building technology is an intense treatment that boosts the efficacy of OLAPLEX Nº.3 Hair Perfector for deeper repair while strengthening and protecting the integrity of the hair. BENEFITS The Nº.0 Intensive Bond Building Hair Treatment boosts the efficacy of OLAPLEX Nº.3 Hair Perfector by absorbing quickly to jumpstart repair deep within the hair strand. Nº.0 Intensive Bond Building Hair Treatment strengthens and rebuilds hair bonds and is scientifically proven: 68% more repair & 3x stronger hair* *When used as a two-part system in just one use. HOW TO USE Apply to dry hair, saturating from root to ends. Hair should be damp, but not dripping. Leave on for 10 minutes. Don't rinse. Layer Nº.3 HAIR PERFECTOR directly over top of Nº.0 and leave on for an additional 10 minutes. Rinse thoroughly. Cleanse with OLAPLEX Nº.4 BOND MAINTENANCE SHAMPOO and OLAPLEX Nº.5 BOND MAINTENANCE CONDITIONER.