The limescale protection cartridge has been specially developed by Swiss engineers at Laurastar and allows tap water to be filtered for ironing. Thanks to its limescale protection feature, the lifespan of your iron is extended. The salt protection effect improves steam quality. The rust protection effect helps maintain the components of the steam generator. The limescale protection cartridge needs to be replaced as soon as the limescale protection granules have turned completely brown. Please note that the appropriate filter insert is required for the use of this cartridge.