The Planet Waves Humidipak Kit lets you maintain a constant 45% humidity level for your instrument, giving you peace of mind and an easy-to-use system. The Humidipak Kit gives you a true "2-way" humidity control, keeping a steady percentage by adding or depleting moisture as necessary. Now you can keep your prized instrument stored without having to resort to messy, refillable units. Protect your investment with the Planet Waves Humidipak Kit.