Boveda’s patented 62% humidity control packs control moisture content, keeping the contents of your containers at the perfect desired level. They don’t need any activation or maintenance. Just place them in an sealed container with your items, and Boveda technology will do the rest. Only Boveda responds to any impressive humidity situations inside a container by adding or engrossing moisture as desired to preserve the determined comparative humidity (rH) level of 62%. Your material will stay fresh, with steady moisture content, delivering a consistently exquisite experience every time. Lasts 2-4 months depending on conditions. Replace when Boveda turns rigid.