Our 401 Furnace Filter Replacement is compatible with AprilAire 2400, Space-Gard 2400 Whole-House Air Cleaner Purifiers. Please check your machine model before purchasing! MERV 13 FIltration: Removes 99.7% of airborne particles down to 0.3 microns in size, such as pet dander, and pollen, creating fresh air for you and your family. Nominal air filter size of 16 x 25 x 6 inches (nominal size is an industry-standard filter size system to help you easily identify the correct replacement filter and is not the actual size). Package include: 4 x 401 replacement filter .It is recommended to replace every 8-12 months (dependent on air quality and use) so you can enjoy clean and filtered air for a long time. Kindly Notes: This product is a generic filter that is designed to replace the original part. Any brand names or logos are the registered trademarks of their respective owners. Any use of the brand name or model designation for this product is made solely for purposes of demonstrating compatibility.