BambooMN Brand Granulated Bamboo Charcoal Odor Absorber in Decorative 4" Cylinder, Brown 2pc 2 pack of Passive Activated Carbon Air Filter/Air Fresheners, each in decorative 4" X 4.5" cylindrical box Each attractive bamboo box contains approximately 200 grams of bamboo charcoal granules in a non-woven filter bag. Bamboo Granules come from a species if bamboo called Moso bamboo. 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.