The black On-Stage GA150 is a sponge-style instrument humidifier designed to provide moisture regulation for an acoustic guitar while it's stored in your home, studio, or shop. The GA150 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 guitar. 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.