Helps reduce white dust, a deposit of minerals caused by hard water. In New Zealand this will be especially relevant for people on a water supply where there is hard water containing minerals - such as bore water. 

For best results, replace filter after every 30-40 fillings under normal use, or 1-2 months, or when the humidifier has not been operated for an extended period. 

To install, simply replace tank cap with filter and wait 15 minutes for the water to pass through the filter before re-starting the humidifier. Helps extending the life time of the humidifier. 

Fits all Crane Drop, Droplet and Adorable Cool Mist Humidifiers.