The Hornady Security Rechargeable Silica Desiccant Dehumidifier is designed to prevent rust or mildew in gun safes or other enclosed areas. 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. Recharging the dehumidifier is easy by simply plugging it into a common 110V wall outlet.FeaturesSafeguards firearms and other valuables from mold and mildewEliminates humidity in enclosed spaces up to 333 cubic feetQuick-connect bracket makes mounting unit easy in gun safes, closets or pantriesRemoves humidity without electricity or batteriesColor-shifting moisture-control crystals signal when recharging is necessarySimply plug in to dry out crystals and recharge unit for renewed effectivenessContains no harmful chemicals - child, pet and home safe