From the Manufacturer This premium WaterSentinel replacement refrigerator water filter contains a 0.5 micron coconut shell compressed carbon block which provides tremendous capacity to reduce impurities 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 absorb 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. WQA Gold Seal Certified to NSF Standard 42 to ensure compliance with industry safety and structural standards, this filter will reduce sand, silt, sediment, rust, chlorine taste and odor and other contaminants that may be in your water. Proudly manufactured in USA, this high quality economical filter will provide crisp, clear and clean drinking water and ice cubes for you and your family. Filter is backed by the WaterSentinel 90 Day Money back Guarantee