Contains 4 replacement wicking humidifier filters.<br><br> Fits the following Models: <br> HCM-300 Series: HCM-300T, HCM-305T, HCM-305T-CST, HCM-310T, HCM-315T, HCM-350, HCM-350B, HCM-350B-CST, HCM-350W.<br> HCM-450BCST. <br> HCM-500 Series: HCM-530, HCM-535, HCM-535-20, HCM-540, HCM-550, HCM-550-19, HCM-551, HCM-560. <br> HCM-600 Series: HCM-630, HCM-631, HCM-632, HCM-632TG, HCM-635, HCM-640BW, HCM-645, HCM-646, HCM-650.<br> HCM-700 Series: HCM-710. <br> HCM-1000 Series: HCM-1000, HCM-1000C, HCM-1010. <br> HCM-2000 Series: HCM-2000C, HCM-2001, HCM-2002, HCM-2020, HCM-2050, HCM-2051, HCM2052. <br> HEV-312, HEV-355.<br><br> Fits Model: ECM-250i<br><br>. Replaces part # HAC-504, HAC-504AW, HAC504V1.<br><br> This is NOT a Honeywell OEM product. The Honeywell and Enviracaire brand names and logos are the registered trademarks of their respective owners. Any use of the Honeywell and Enviracaire brand names or model designations for this product are made solely for purposes of demonstrating compatibility..