Boveda 2 Way Humidity Control Pack for Ukuleles - Ukulele Humidifier 49% - Size 70

Without proper humidity control, wood instruments will not perform at their maximum ability and even worse can be damaged. To maintain their shape, wooden instruments need to be stored at a stable 45-55% RH (relative humidity). Wide fluctuations in humidity will cause the wood to expand or shrink, which puts stress on the instrument and degrades its performance abilities.

Stop risking your instrument by adding water. Only Boveda’s patented 2-way humidity control adds or removes moisture as conditions require to maintain the ideal humidity level in your instrument case. Boveda helps prevent warping or cracking, and eliminates downtime for service. Because Boveda requires zero maintenance, your instrument will always be protected.

 These are super easy to use as they don't require constant maintenance like most humidifiers. Just put it in the case and you're good to go.