Filter includes HEPA, Carbon, and Pre-Filter. Compatible with Surround Air MT-8400SF Air Cleaner. HEPA filtration helps remove dust, pollen, mites, and pet dander, Pre-filter captures larger particles, carbon removes odors, chemical vapors, and cigarette smoke. For optimal performance, it is recommended replacing filter every 6-months (dependent on air quality and use). Approx dimensions: 11-1/4' x 11-7/8' x 1' thick - By LifeSupplyUSA.