P5-D Culligan Level 4 Whole House Filter Replacement Cartridge (2-Pack)
Product Review (submitted on January 5, 2010):
our well water has iron bacteria and tannin. The 20 and 5 micron filters keep our lines clear water good. Depending on rain or snowfall these filters which are mounted out in our well house and filter ALL house water last between 6 and 8 or so weeks.