The mounting system allows the humidifier to hang horizontally inside of the ukulele</br>The humidity output is about 50% of the Royal Blue Oasis guitar humidifier?? to accommodate the smaller instrument size</br>This humidifier lasts twice as long between refills</br></br>Product Description</br></br>OH-18 Ukulele Humidifier</br><br/>http://www.amazon.com/gp/product/B0036FFKE2