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. Absorb humidity and prevent rust or mildew in gun safes or other enclosed areas. Moisture control crystals change color when unit needs recharging. Recharge by plugging into 110 V electrical outlet. Safeguards firearms and other valuables from mold and mildew Eliminates humidity in enclosed spaces up to 333 cu-ft Quick-connect bracket makes mounting unit easy in gun safes, closets or pantries Removes humidity without electricity or batteries Color-shifting moisture-control crystals signal when recharging is necessary Simply plug in to dry out crystals and recharge unit for renewed effectiveness Contains no harmful chemicals - child, pet and home safe