Lockdown Rechargeable Silica absorbs moisture from the air inside a vault or storage area preventing condensation, mildew and rust from damaging valuable firearms. Crystals change color once fully saturated and can be easily recharged in the oven.- Absorbs Moisture From The Air - Individually Wrapped 40 gram Silica Bags - Indicator Card in Each Wrapper Shows When It’s Time To Recharge - Ideal for Handgun Vaults and Ammo Cans - Changes from Blue to Pink when it needs to be recharged