For particularly pleasant air humidification: The replaceable, absorbent filter of the Soehnle Airfresh Hygro 500 humidifier captures large particles such as hair and dust when drawing in dry air. It also protects the Airfresh Hygro 500 from dirt. Replaced regularly, the filter provides your air with new, fresh water molecules while maintaining the same high humidification performance. The filter can be removed and replaced quickly and easily.