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. Size 5.2 fl oz Benefits: •Boosts the efficacy of OLAPLEX Nº.3 Hair Perfector®. •Absorbs quickly to jumpstart repair deep within the hair strand. •Strengthens and rebuilds hair bonds. •Scientifically proven: 68% more repair & 3x stronger hair.* •Color safe and sulfate free.