!!! PLEASE NOTE: Our carbon filter is NOT a foam pre-filter on the Air inlet grill! It does NOT replace this foam pre-filter for the front cover! Carbon filter is a booster filter you apply directly to the FRONT of the HEPA-type (AER1) filter for absorption of any household unfavorable odors. So airflow will first go through the foam filter on the front grill of the device, then it will travel through the carbon booster filter, then finally through the HEPA-type (AER1) filter.
Compatible with: Holmes HAP9412, HAP9413, HAP9414, HAP9415, HAP9421, HAP9422, HAP9423, HAP9424, HAP9425 Air Purifiers, Holmes BHOR31-1 AOR31 AOR31-U carbon filter Replacement.