The Zuvo Water ZFS159 undersink water filtration system is designed using Zuvo Water’s patented 5-step process to produce great tasting, healthy water. The 5 steps in this process are: ozonation, ultraviolet purification, photo-oxidation, filtratration with lead removal and post-UV filtration. The 100 series models also have smart technology featuring a built-in buzzer to indicate filter life and operation status.From the ManufacturerThe Zuvo Water ZFS159 undersink water filtration system is designed using Zuvo Water’s patented 5-step process to produce great tasting, healthy water. The 5 steps in this process are: ozonation, ultraviolet purification, photo-oxidation, filtratration with lead removal, and post-UV filtration. The 100 series models also have smart technology featuring a built-in buzzer to indicate filter life and operation status.