Hydronix SDC_45_2005 SDC-45-2005 5 Micron Whole House 20 x 4.5 Sediment Water Filter 6 Pack, Single Unit, White 5 micron fine sediment filter for cleaner water Graded density for higher dirt holding capacity For optimum dirt-holding, replace about every 2-3 months Materials ANSI/NSF Standard 42 tested and certified