Extend the life of your treasured acoustic instrument with the 2-way humidity control kit from Boveda. Fluctuating humidity levels can wreak havoc on your acoustic instrument, causing it to warp, shrink, and crack. Not only does that ruin your instrument’s aesthetics; over time, it can ruin its tone or, ultimately, render it unplayable. Boveda’s unique product uses a specially formulated pure water and natural salt solution encapsulated in a water-vapor permeable membrane to maintain a constant relative humidity level of 40%–50% when placed alongside your instrument in its case, preventing devastating humidity fluctuations. So, you can rest assured that your instrument is kept in an ideal environment. This large starter kit contains four 70-gram 49% relative humidity packets and two fabric 2-pouch saddlebags, ideal for acoustic wood instruments.