Dry-Packs Indicating Silica Gel 40 Grams in Sturdy Aluminum Dehumidifying Canister - No Cobalt Chloride II - DP40CAN Dry-packs sturdy aluminum canister easily reactivates so you can reuse over and over again Indicating window turns orange to dark green when canister needs reactivating Electric free dehumidifier no cords - protects 3 cubic feet.