20 x 4.5 Inch Carbon Whole House Filter C2-02 Fits IHS12-D4 and IHS22-D4 Systems Genuine OEM product Reduces chlorine taste and odor in your water down to 10 micron Filter media constructed from renewable coconut shell Replace every 3 months Fits most 20 x 4.5-inch filter housings including the Viqua IHS12-D4 and IHS22-D4 water disinfection systems