4-stage water filter is positioned after PDAM house, or on your main water piping. Each tube has different filtration media that allows easier cleaning and maintenance. Tube#1 has activated sand that reduces Fe content and odor in water. Tube#2 is filled with manganese greensand to absorb Mn, Fe, and H2S in the water. Tube#3 contains activated carbon to purify water, and tube#4 is filled with zeolite sand to adsorb organic compound and heavy metals, as well as improving the water's taste and odor.