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.Specifications and Features:Absorbs Moisture From The AirIndividually Wrapped 40 gram Silica BagsIndicator Card in Each Wrapper Shows When It's Time To RechargeIdeal for Handgun Vaults and Ammo CansChanges from Blue to Pink when it needs to be recharged