Oasis Plus+ Guitar Humidifier You can see when Oasis is ready for refillLong lasting humidificationWon't leak due to overfillingTwo levels of leak protectionStabilized to Never Touch the Body of Your Instrument The humidity demands of the desert, mountain states or frigid north exceed the humidification capacity of the device For this reason, Oasis developed the Oasis Plus+ humidifier The Plus+ is the same size and shape as the original blue Oasis, but is made of a different material that provides 50% more humidity output Because the Oasis Plus+ Humidifier is the same size as the original Blue Oasis and it has 50% greater humidity output, it will be necessary to refill the Oasis Plus+ more frequently than the original Blue Oasis