L’Oréal Professionnel Serie Expert Curl Expression, 200 ml, Hair Creams and Gels for Women, The L’Oréal Professionnel Serie Expert leave-in treatment gives your hair everything it needs after washing. Characteristics: provides hydration and nourishment for your hair leaves hair beautifully shiny and full of vitality How to use: Apply to towel-dried hair. Do not rinse.