V5-Cell Gas Phase Filter Cartridge. F2 on your Control Panel. Replace every 1-2 years. Replacement filter fits the IQ Air Healthpro PLUS. Special: We pay any applicable sales tax. Specifications: 5 lbs of activated carbon and alumina impregnated with potassium permanganate. See part #5 in the image for orientation. Ships free in the continental United States. IQ Air Part # 102181000