Purenex 1S-20BB-1C-20BB 2 Cartridges for 20-Inch Big Blue Whole-House Water Filters Block Activated Carbon filters - 20" Big Blue Melt-blown Polypropylene Sediment filters - 20" Big Blue individually wrapped, packed in 2 PCS per carton Micron rating: 5 Micron Dimensions: 20" x 4.5"