L’oreal Professionnel Absolut Repair Molecular 4-step Kit. STEP ONE – Professional Concentrated Pre-Treatment 3.4 FL OZ. (only 15 pumps needed per treatment) leave on 1-2 minutes. Don’t rinse out. STEP TWO – Professional Shampoo 16.9 FL OZ. Shampoo with Pre-Treatment in hair. STEP THREE – Professional Rinse-Off Serum 8.4 FL OZ. Split hair into sections, 1-2 pumps per section. Apply root to tip. Leave on 1-2 minutes. STEP FOUR – Professional Leave-In Mask. Apply on towel-dried hair. A little goes a long way. Use the full system no more than once a week.