The Stack-On SPAD-60 Safe-N-Dry Moisture Elimination Packet pulls moisture from the air to prevent humidity from damaging valuables and can be used almost anywhere. Each packet is individually wrapped in a foil pouch to prevent the desiccant from activating. Once opened each packet can draw moisture from 5 to 7 cubic feet for about 6 weeks before it will need to be recharged. Recharging is accomplished in a standard, vented oven at 200 degrees F for 3 hours and can be recharged approximately 3 or 4 times before its moisture absorbing properties are lost. Each packet includes a handy moisture indicator to let you know when it is time to recharge.