AeraMax SV combo filter set offers three functions: combined H13 True HEPA and carbon filter plus separate prefilter to capture larger particulate to help extend life of subsequent filters. Actual filter dimensions: 23.25"H x 11.56"W x 2.38"D | Fellowes AeraMax SV HEPA/Carbon Air Purifier Filter with Prefilter, 23 x 12 x 2, 2 Sets/Pack (978790 | Quill