This Kwik-Change UF3 annual replacement filter pack includes one Kwik-Change sediment red label filter, one Kwik-Change carbon block yellow label filter and one Kwik-Change UF membrane violet label filter. The sediment filter traps sediment and other particulate matter, such as silt, dirt, and rust which affects the taste and appearance of the water. The 5 Micron filtration rating is in the particle filtration category and is equivalent in size to milled flour. For best results this filter is designed to be changed out every 6 months or every 1,350 gallons. The five micron carbon block filter reduces chlorine, objectionable tastes and odors. The UF hollow fiber filter, a membrane filtration process which uses standard home water pressure to push water through its semi permeable membrane. The suspended particles and materials of high molecular weight are unable to pass through the .2 micron UF membrane, leaving only fresh clean water and dissolved minerals to pass through.