The unique Cigar Oasis XL is a small electronic humidifier that is fully automatic. Just plug it in using a paper this power cord that fits between the hinges on the back of the humidor, or connect the optional battery pack and it's ready to go. The integral hygrometer displays the humidity in the humidor and it is also used to set the controls point which is factory set at 70%RH. This can be adjusted. The unit comes with a refillable, replaceable water cartridge that uses distilled water only. It has a built in system that monitors the humidity and uses a quiet fan to filter and circulate air in the humidor.