antibacterial treatment keeps the material clean. The humidifier filters should be replaced every 2 months in order to maintain hygienic humidification and a high level of effici…The humidifier filters ensure that evaporators Oskar little, Oskar and Oskar big optimally humidify the air. The humidifier filters are manufactured from plant and textile fibres and do not contain any plastic at all. The antibacterial treatment keeps the material clean. The humidifier filters should be replaced every 2 months in order to maintain hygienic humidification and a high level of efficiency.