Refrigerator filters designed by water treatment professionals to provide great tasting water and ice cubes at an economical price. WaterSentinel® refrigerator water filters contain a compressed carbon block which provides tremendous capacity to reduce impurities and sediment that may be present in your drinking water. The carbon block has millions of active sites on its surface and within the structure which can adsorb impurities like a sponge, and can adsorb and hold other types of impurities on its surface like a magnet. Additionally, this filter can catalytically breakdown other impurities very similar to the way a catalytic converter works in your automobile. These processes ensure that you are getting the cleanest and best tasting water possible.