Activated carbon block filters with sub-micron ratings go above and beyond to remove additional particles through mechanical filtration. Mechanical filters work like a screen door-- they keep unwanted elements out and let clean water through. Pores of a carbon block filter that measure less than one micron are too small for cysts to pass through.
1.Effective taste, odor, and chlorine reduction
2.Lots of surface area
3.Reduced health hazards
4.Protection for other filtration systems or softeners