The Brondell H2O+ Cypress Carbon Block filter (HF-33) is the final stage in the advanced Cypress filtration system. The Carbon Block filter further reduces particulates, bad tastes and odors, and water contaminants such as chlorine and harmful volatile organic compounds (VOC"s), improving the taste of the dispensed water. The HF-33 filter significantly reduces harmful chemicals like Atrazine; Chlorobenzene; Trihalomethanes; Methoxychlor; Endrin; 2,4-D; Benzine; DBCP and 98% of Aesthetic Chlorine from your tap water for a healthier home and family. Choose Brondell H2O+ for better water.The 3-stage H2O+ Cypress H630 water filtration system:*Stage 1: COMPOSITE PLUS FILTER (HF-31): This 2-step filter reduces particulate materials such as sand, rust, and fine particles from the water supply. This first filter also acts as a pre-filter protecting the 2 following filters. Recommended replacement every 6 months.Stage 2: NANOTRAP FILTER (HF-32): This specialized, patented, innovative Nanotechnology filter is made with 100% USA sourced materials including Nano alumina & cellulose fibers with a pore size of 2 micron (2 µm) that reduce turbidity, harmful waterborne microorganisms (including many bacteria and virus) as well as numerous particulates. Recommended replacement every 12 months.Stage 3: CARBON BLOCK FILTER (HF-33): As the final stage in the filtration process, the Carbon Block filter further reduces particulates, bad tastes and odors, and water contaminants such as chlorine and volatile organic compounds (VOC"s), improving the taste of the dispensed water. Recommended replacement every 6 months.The HF-33 filter when used with the H630 system is tested and certified by WQA to NSF/ANSI Standards 42 for Aesthetic Chlorine, taste and odor, Particulate Class 1 and 53 for VOC reduction.Do not use with water that is microbiologically unsafe or unknown quality without adequate disinfection before or after the system.