The humidifier has an open-cell phenolic foam insert rather than
ordinary sponge. The foam shrinks less than 1% when dry vs. sponge,
which can deform dramatically, resulting in leakage. The humidifier
is also equipped with a syringe, which allows you to control the
amount of water used when filling or refilling the humidifier.
Maintaining the humidifier is as easy as squirting distilled water
into the nozzle when the element begins to dry. The frequency
of maintenance will vary considerably depending on your specific
atmospheric conditions. Product of J.D'Addario.