IonTech ACF-1 Replacement Filter for Alkaline Water Ionizer Activated Carbon Filter has higher absorption efficiency than coconut shell granular carbon filters Works with IT-530 IT-580 IT-589 IT-656 IT-750 IT-757 Alkaline Ionizers Industry-Leading Manufacturing Technique complies with the highest drinking water standards Certified Manufacturer with over 15 years of experience Long-Lasting - 1,500 - 3,000 Gallons of Water