Music Nomad MN303 Case Humitar Instrument Case Humidifier with Holster Instrument case humidifier safely releases moisture evenly to eliminate warping, shrinking, and cracking Case holster comes with a strong adhesive to stick in the case Innovative Humid-I-Bar sponge holds 10x its weight in water and features anti-drip, no-mess material that safely releases moisture Easy-to-use, long-lasting, low-maintenance humidifier for guitar, mandolin, cello, and other large case instruments Convenient quick-flip top lets you check if Humid-I-Bar sponge is wet or dry