Omnifilter RS1-SS24-05 Pleated Paper Whole House Replacement Cartridge: * Reduces rust and sediment * For use with the Whole House Water Filter OB1 * Included in Whole House Water Filter R12 * Pleated paper * 3 months or 15,000-gallon average cartridge life * 5 GPM flow rate * 20-micron rating * Single pack