D'Addario Screeching Halt Humidifier
"The D’Addario Screeching Halt Humidifier allows you to humidify your guitar’s body and neck joint, even in the driest conditions—while on display, or during extended periods when your instrument will be outside its case. The humidifier releases moisture slowly and evenly while capturing the vapor inside the body of the instrument to retain the proper humidity level. Maintaining the humidifier is as simple as moistening the sponge when the humidity falls below a safe level (40-60% Relative Humidity). The Screeching Halt Humidifier can also be used as a feedback reducer when playing live, keeping your guitar properly humidified even during performances."