Music Nomad MN300 Humitar Acoustic Guitar Humidifier Long-lasting, low-maintenance acoustic guitar humidifier Safely releases moisture evenly to eliminate warping, shrinking, and cracking Innovative Humid-i-Bar sponge holds 10x its weight in water and features anti-drip, no-mess material Convenient quick-flip top lets you check if Humid-i-Bar sponge is wet or dry Hangs from the strings to safely release moisture in sound hole