The Dampit 9127 Guitar humidifier is essential for any acoustic guitar player out there!! By controlling the humidity in your guitar, you prevent it from cracking and splitting, especially in the dry winter months. When the guitar is deprived of humidity, the neck will move, frets can become sharp and playing your guitar can become a nightmare. With this easily to use sponge, you just soak it in water, shake off the excess and put it in the sound hole of your guitar while its resting in the case. It's just that easy!!