L'Oréal Professionnel Serie Expert Pro Longer Mask 250ml is a targeted treatment designed for long hair with thinning ends. Infused with the patented FILLER-A100 technology and Amino Acids, it penetrates the hair fiber to thicken ends from within while reinforcing strength externally. This professional-grade mask reduces split ends by up to 66%, leaving hair visibly fuller, shinier, and healthier. Ideal for those seeking to maintain long, strong locks, it works best when used after the Pro Longer Shampoo. Apply to towel-dried hair, leave on for 3–5 minutes, and rinse thoroughly for optimal results. ​