Boveda creates a monolayer of purified water molecules that naturally shield your products until use. Restore and maintain with the global leader in two-way humidity control. Place Boveda in packaging for precise Relative Humidity (RH). All natural salts and pure water inside keep contents fresh for 2-4 months in airtight containers. Just replace when Boveda is rigid. The Resealable high-barrier plastic bag is factory-sealed. Keep the zipper closed and you can expect unwrapped Boveda to stay fresh for up to two years before you’re ready to put them to use.