Acoustic Guitar Soundhole Humidifier, Black ,Moisture Reservoir ,Silver Humidifier is designed for protecting your guitar in the driest conditions Suspended by the strings , the humidifier releases moisture evenly & slowly inside your guitar Fill in the distilled water into the nozzle about once a month for maintaining the humidifier Distilled water should be used . No Tap water Size : 85mm x 80mm x 33mm