The DAddario Screeching Halt Humidifier is perfect for humidifying your guitar whilst out of the case. The humidifier releases moisture slowly and evenly for the perfect amount of humidity. Simply soak the sponge when the humidity falls. The sponge can hold up to 12x its own weight in water. The DAddario Screeching Halt Humidifier can be used as a feedback reducer when playing live keeping your guitar humidified even mid performance. This model quickly and easily installs into a 4 soundhole.