Moisture is the enemy of your firearm collection, but you can fight it with this dehumidifier. Put this reusable unit inside your gun safe to absorb excess moisture in the air that can cause rust and corrosion. It also raises the temperature inside your safe, increasing the spread between the air temperature and dew point temperature to decrease relative humidity. Dehumidifies approximately 100 cu. feet of space for the 12, and 200 cu. feet of coverage for the 18 dehumidfier. Imported. Lengths: 12 - Covers 100 cubic feet 18 - Covers 200 cubic feet Cancer and Reproductive Harm- www.P65Warnings.ca.gov. Type: Dehumidifiers.