4-Stage Replacement Mineral Filter Cartridge for Zen Countertop & Water Cooler Water Filter Systems Comprised of Silver Impregnated Granular Activated Carbon & 19 Natural Minerals Original Replacement Filter for your Zen Water Filter Systems Fits 4, 6 and 8 Gallon Countertop & Water Cooler Filter Units. This is NOT for your 3 Gallon Model Healthy Purified Mineral Water from your Tap. Highly effective in removing all impurities, bacteria, color, chemicals, organic and inorganic chemicals from your tap water