This Refrigerator Water Filter is used in refrigerators with filter access inside the refrigerator. Simply turn the filter to remove and replace. While retaining beneficial fluoride, this NSF® Certified filter reduces cysts, chlorine taste and odor, particulates (class I), lead, and mercury. The contaminants or other substances removed or reduced by this water filter are not necessarily in all users' water. Replacing this filter every 6 months ensures clean, safe drinking water. Replaces UKF7003AXX, UKF5001AXX, UKF7001AXX, UKF7002AXX.