The black On-Stage GA250 is a sponge-style instrument humidifier designed to provide moisture regulation for an acoustic ukulele while it's stored in your home, studio, or shop. The GA250 hangs inside the instrument’s soundhole by hooking onto the strings. This suspension method allows it to disperse moisture consistently without touching the body of the ukulele. Through proper humidification, you can protect your instrument against harmful conditions such as dry climates, which can cause warping and cracking of the body’s wood.