Surround Air MT-8500SF 3-in-1 Spare Filter with Professional-Grade HEPA, Activated Carbon and Pre-Filter 3-in-1 spare filter cartridge includes true HEPA, activated carbon and pre-filter True, professional-grade HEPA air filter for dust & allergens: pollen, ragweed, mites, mold spores Activated carbon filter for odors, chemical vapors and cigarette smoke. Extremely absorbent Cleanable pre-filter for larger particles, prolonging performance & lifespan of other filters