Redken Extreme Length Shampoo and Conditioner DUO Set (1 Liter Each). Helps achieve up to 6 inches of growth in one year. Length Fortifying Complex contains Biotin , a vitamin known for its ability to promote healthy hair growth. Strengthens hair from root to tip, reducing breakage by 81%. Formulated with 1% Length Care Complex to strengthen damaged hair. Helps promote strong hair. Formulated with 4% Length Care Complex. Helps strengthen fragile strands and ends for longer hair. Provides nourishment and conditioning. [1 Bottle] Redken Extreme Length Shampoo (1L). [1 Bottle] Redken Extreme Length Conditioner (1L).