The two-stage V5-Cell Gas and Odor Filter uses dual media to filter a wider spectrum of volatile organic compounds (the cause of odors) and other harmful chemical vapors. Granular activated carbon adsorption and pelletized chemisorption work together to go beyond conventional activated carbon filters found in ordinary air purifiers. Complements the PreMax Pre-Filter and the HyperHEPA Filter. Lasts up to 2 years (based on average daily usage of 10 hours on speed 3).