A part of the Cypress countertop filtration system from Brondell, this filter ( HF-33 ) works as the final stage of the filtration system. One of the three needed for the Brondell Cypress, the HF-33 is the Carbon Block fitler. This filter further removes particulates, bad odors and tastes, and other water contaminates. It has a 98% reduction of Aesthetic Chlorine and can be changed every 6 months.