The Hornady Security Rechargeable Dehumidifier is filled with desiccant crystals designed to absorb moisture from your safe, closet, tool chest, or other enclosed area. As the desiccant crystals fill with moisture they change from blue to pink. It eliminates humidity up to 33 cubic feet and contains no harmful chemicals. Recharging the dehumidifier is easy by simply plugging it into a common 110V wall outlet.