The limescale filter cartridge, specially designed by Laurastar Swiss engineers, allows you to filter tap water before it is used for ironing. (Please note that the water tank holder is required to use this cartridge which is already included in SMART systems.) Demineralizion gradnules inside a protective cartidge that filters tap water to make perfect water for steaming and prolongs the lift of your iron. Main Features By preventing limescale, it prolongs the life of your iron By filtering salts, it improves steam quality Anti-corrosive, it also prevents damage to boiler components The limescale filter cartridge should be replaced when anti-scale granules turn completely brown Compatible Systems Laurastar SMART 1980 Laurastar SMART U Laurastar SMART I Can be used with S series models with purchase of a holder for SMART anti-scale cartridges.