Excellent for larger spaces, this non-electric heavy duty dry vapor dispenser features adjustable airflow to maximize customization. Used in relatively low air movement environments like large self storage spaces, boats, RVs or storage semis, the Mintek Heavy Duty Stand Alone Cartridge can last for up to two months or more of continuous use. Based upon our proven products used in disaster restoration services, the new Mintek HDSA is easy and versatile: simply dial open the aluminum plates at both ends, opening the air passages allowing vapor to be released and locate near the access points where mice, rats, or other common pests enter. Can treat large areas up to 20,000 cubic feet. Creates an unpleasant environment for pests, but, a pleasant mint smell for humans. Product will begin working immediately. Non-toxic. Spill-proof.