The OLAPLEX Ultimate Bond Repair Duo includes the powerful combination of No. 0 Intensive Bond Building Treatment and No. 3 Hair Perfector to deliver professional-grade bond repair at home. No. 0 primes and prepares the hair to maximize the benefits of the treatment, penetrating deep within the hair fiber to rebuild and strengthen. No. 3 continues the repair process by nourishing and strengthening the hair, improving its overall health and restoring its natural shine. This dynamic duo works to dramatically reduce breakage, repair damage, and promote healthier, more resilient hair with every use.