The Gonzo Smell Proof Bag has an innovative design. It is made of double walled 4 mil thick plastic with an activated charcoal filter to contain 100% of odors. This filter contains a whopping 30 grams of industrial quality activated carbon per square foot on each side of the bag. Each bag has a roll top design with built in Velcro for an easy, quick seal. This also allows the Gonzo Bag to be reused again and again. If used correctly, even animals can't smell what's in the Gonzo Bag!