AHAVA Clineral PSO, 200 ml, Hair Masks for Women, The AHAVA Clineral PSO hair mask is an essential step in your hair care ritual. Give it a moment to regenerate and it will repay you with vitality and beauty. Characteristics: moisturises intensely How to use: Wash with shampoo, then apply to damp hair. Leave to act as instructed on the packaging, then rinse thoroughly.