It is essential to maintain a proper moisture level in your guitar. Grover's new guitar case humidifier helps to prevent adverse effects such as bad string action, buzzing, protruding fret ends, cracking, top-sinking, and other damage caused as a result of dryness. Made of soft latex which is harmless to all instrument finishes, these humidifiers maintain proper humidity levels. Includes a cover to seal the sound hole during use. Easy to follow instructions and a user-friendly humidity gauge are included.