D'Addario Acoustic Guitar Humidifier with Digital Humid/Temp Sensor - Music Freqs Store
Amazon.com: Electric Guitar and Bass 2-way Humidity Control Packs(2 Packs with Pouches, 2 Airtight Bags), 49% RH Humidifier-Dehumidifier Wood Instrument Care Starter Kit with Self-hydrometer and Polish Cloth : Appliances