[Confirm models] Four packs of HFT600 humidifier core suction filter T are applicable to most models: HFT600, HE615 series - HEV615, HEV615B, HEV615 W, HEV-615, HEV-615B, HEV-617W, HEV620 series - HEV6 20, HEV620B, HEV6 20W, HEV 620, HEV-620B, HEV 620W. Replace the part HFT600T HFT600PDQ. [More size details] note that this package has 4 sets of blue HFT600 replacement core suction filter T, with the size of 7.6 inches x 6.5 inches x 1.3 inches. Note: Do not use bleach, soap or vinegar to clean the filter. [Keep from dryness] Keep it moist this winter. Install wicking filter T to maintain the maximum moisture output of the humidifier and help prevent dry and itchy nose and throat. [Maximum 30-60 ] replace the filter 30-60 to maintain the maximum moisture output of the humidifier. The filter T also needs to be replaced when the following conditions occur: 1. When the filter becomes hard, crusts and smells; 2. When a decrease in moisture output is . Colour:blue Material:wood pulp paper Package Contents: 4 x filters Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.