These easy two way humidity control packs continually respond to surrounding conditions by adding or removing moisture. It's simple to use. Just put the pack in the cloth envelope and set it in your case! The rest of the work is done for you. Whenever the pack becomes dry and hard, that means it's time to replace. One pack is needed for violins or violas, and two packs are needed for cellos.
This starter kit comes with one cloth envelope and two Boveda refill packs.