No.3 Hair Perfector, with patented Olaplex Bond Building technology, is a pre-shampoo treatment that repairs and strengthens hair from the inside. - Nº.3 Hair Perfector reduces breakage and visibly strengthens hair - Nº.3 Hair Perfector repairs and protects the depths of each strand of hair - Nº.3 Hair Perfector restores a healthy look and texture. How to use: Apply it to damp hair from roots to ends. Leave it on for 10 minutes to maximize effectiveness. Rinse well.