This is nothing short of awesome. Having moved to a city with Chloramine in the water supply, I started getting psoriasis (for the first time in my life) after just a few weeks. Fitting this on my shower stopped the psoriasis completely - and continues to after four months. I forgot about it and started getting itchy patches - looked and realised the cartridge needed changing again. New cartridge - itching gone. It also makes a BIG difference in the condition of hair. HIGHLY RECOMMENDED.