I'm selling this because I don't use it anymore!! Free Science Sorui Water Shower Cartridge While the residual chlorine (hypochlorous acid) in tap water eliminates bacteria, it's actually harmful to hair and skin. If you shower directly with tap water, the effects of your shampoo and other products will be halved, no matter how much you care about them. "Water Therapy" effectively removes residual chlorine with fast-absorbing fiber activated carbon, making it safe for even babies' skin. When residual chlorine combines with the proteins in hair and skin, it can damage the hair cuticle and skin cells, leading to split ends and skin irritation.