Our 401 Replacement Furnace Filter Compatible with AprilAire 2400, Space-Gard 2400 Whole-House Air Cleaner Purifiers - MERV 13. Product Dimensions ?: ? 25 x 6 x 16 inches Package Include: 4 Pack It is recommended to replace every 6-12 months depending on the usage and environment. Disclaimer: 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 to demonstrate compatibility.