D'Addario's Planet Waves Acoustic Guitar Humidifier; The number one cause; major guitar repairs; lack; humidification. Humidifying your guitar; an essential step; maintaining your instrument. The best selling D'Addario Acoustic Guitar Humidifier makes; easy; properly and safely humidify your guitar. The Humidifier hangs safely; the sound hole suspend; the instruments strings; it never touches the body; the instrument. Simply moisten the sponge, install and that's it. The humidifier releases the moisture slowly and evenly keeping your guitar perfectly humidified. When the sponge becomes completely dry, moisten; again and insert back into the soundhole; Sound hole suspended guitar humidifier Never touches instrument body Releases moisture evenly Sponge Style Humidifier Safe for all acoustic guitars