Cartouche anti-calcification

excellent product!

I understand the need to replace this filter as time goes since it was designed to fight scaling, which involves absorbing minerals in the water. The minerals scale the filter instead of the machine and you should buy another. The company recommends replacing the filter so I'll have to take their word for it to avoid getting ill. I seriously recommend learning how to take care of yourself by taking care of your cool-mist humidifier's maintenance. They are great humidifiers but are the most prone to bacteria formation if ill maintained and you can get sick!

Very easy to change, fits nice and tight.

Works well, easy to install.