Reconstructing masque that intensely replenishes brittle and damaged hair. Masque Force Architecte reconstructs the hair fiber while intensifying its strength from root to end. To use: Apply a small amount to lengths and ends of hair, focusing on mid-lengths to ends. Leave on for 5-10 minutes and rinse thoroughly. For best results pair with Kerastase Bain Force Architecte for the ultimate reconstructing cleanser, Ciment Anti-Usure as a conditioning treat, and Fibre Architecte serum as a leave in daily hair protectant.