4 pack of Passive Activated Carbon Air Filter/Air Fresheners, each in decorative 6" X 6" X 1 3/4" box * Each attractive bamboo box contains 250 grams of bamboo charcoal granules in a non-woven filter bag. * Bamboo Charcoal helps improve indoor air quality by absorbing and trapping odors, allergens, and harmful VOCs. * Re-usable for years, just place inner bags in bright sunlight for a couple hours twice a month to renew odor absorbing capability of the charcoal. * The activated carbon in these air fresheners is derived from environmentally friendly bamboo.