Carbon cartridges remove contaminants that affect taste and odor by utilizing activated carbon in the form of solid block or granular carbon. Additional features are available with higher quality carbon cartridges, such as, removal of chemicals, bacteria, giardia and cryptosporidium cysts, or lead and heavy metals. Estimated flow rates for carbon cartridges are based on 60 PSI feed pressure. With reduced pressure,the flow rates will be somewhat less than the estimates. These cartridges are all 10" except for the last option, which is a 5" cartridge. For more information about carbon filters, see Information About Water Filtration.