Humidifier for Ukulele, Black ,Moisture Reservoir ,Black Humidifier is designed for protecting your guitar in the driest conditions Suspended by the strings , the humidifier releases moisture evenly & slowly inside your ukulele 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 : 58mm x 54mm x 24mm