Oasis Case Plus+ Humidifier Provides 50% more humidity output when compared to the original Blue Oasis guitar humidifier, but is conveniently the same size. Recommended to be used when the room humidity is below 25%. Ideal for the desert, mountain states or frigid northern environments. The Oasis Case Plus+ Humidifier can be used in stringed instrument cases such as violin, viola cello, guitar, or mandolin. Our case style humidifiers attach to the inside of your instrument case Simple installationYou can see when Oasis is ready for refillLong lasting humidificationWon't leak due to overfilling