Replacement pads for wicking water across the humidfier heater bar. We recommend replacing pads twice a year, or when mineral deposits render them ineffective. Includes:(4 EACH) 30-inch pads(1 EACH) Clear Liner for an older "tall" Vertical Tank(1 EACH) Black Liner for Universal Tanks (current style)(1 EACH) Clean Sleeve for Humidifier Heater Bar