AC INFINITY, DUCT CARBON FILTER, AUSTRALIAN CHARCOAL, 4-INCHIn Store Location: K4 The high airflow duct filter is designed to use activated carbon to eliminate odors and chemicals, popularly used for hydroponics, grow rooms, kitchens, smoking areas, and other ventilation projects. Features premium grade Australian Virgin charcoal bed. The filter can be used in conjunction with an inline duct fan to act as both intake and exhaust configuration. Heavy duty construction contains aluminum flanges and dual sided