The 3US-AF01 Comparable Undersink Filter Replacement Cartridge (3-Pack) by Tier1 is manufactured to fit the 3US-AS01 Undersink Filter System. Each US-WF0120 reduces chlorine taste and odor, sand, soil, silt, rust and and more. The US-WF0120 is built to last for up to six months, depending on use and water quality, making maintenance quick and easy. Order the 3US-AF01 Comparable Undersink Filter Replacement Cartridge (3-Pack) by Tier1 today!