The Nº.4P Blonde Enhancer Toning Shampoo, infused with patented OLAPLEX Bond Building Technology, is a highly concentrated purple shampoo that cleanses, tones and repairs with a sulfate-free formula that neutralizes brassiness and boosts brightness after just one use. Nº.4P Blonde Enhancer Toning Shampoo neutralizes unwanted brassiness and yellow tones. Nº.4P Blonde Enhancer Toning Shampoo cleanses without stripping and drying. Nº.4P Blonde Enhancer Toning Shampoo is Sulfate free and PH Balanced. Flexible timing allows for a more customizable end result. Nº.4P Blonde Enhancer Toning Shampoo is scientifically Proven: 3x brighter* HOW TO USE Dispense desired amount of product into hands and emulsify. Apply to wet hair, distributing evenly. Lather fully and leave on 1-3 minutes. Rinse. For more intense toning, leave on hair or up to 5 minutes. For best results, follow with Nº.5 BOND MAINTENANCE CONDITIONER or Nº.8 BOND INTENSE MOISTURE MASK for extra moisture.