Our 1051 2 Stage Air Filter humidifier water media filter is compatible with AIRCARE/Essick 1051 Evaporative Humidifier. For humidifier models 4DTS300, 4DTS900, 696400HB, 696800, H12300HB, H12400HB, H12600. Please check your machine model before purchasing! FEATURES: Performance Filtration: 1051 humidifier filter replacement effectively does a very good job of filtering out the hardness minerals in the water and prevents a white powder from entering the room air and depositing on everything in sight. Easy to Install: Hassle-free and user-friendly, the replacement process is quick and straightforward. Take out and replace your machine unit when needed. Package include: 2 X 1051 humidifier water filter Warm Tips: We recommend you to replace the 1051 humidifier water filter every month for optimal performance (depending on your usage and environment). It is fairly easy to install, no tools required. Simply take out and replace from your machine unit when needed. DECLARE: This is not an OEM product. Any brand names or logos are the registered trademarks of their respective owners. Any use of any brand name or model designation for this product is made solely for purpose of demonstrating compatibility.